Granted Patent B2

US 7,600,561 · App. 10/539,942 · Granted Oct 13, 2009

Abstract

Claims (12)

1. A method for air conditioning a passenger compartment of a vehicle, said method comprising:

providing heat from a passenger compartment heat exchanger to the passenger compartment through heat pump operation of a refrigerating circuit ( 1 ) comprising a compressor ( 2 ) for pressurizing an automobile refrigerant, a condenser ( 3 ), a throttle valve ( 4 ) and an evaporator ( 5 ) used as a passenger compartment heat exchanger;

measuring the temperature in the passenger compartment with a temperature sensor;

measuring the atmospheric humidity in the passenger compartment with a humidity sensor; and

when the temperature is in a predefined range and the atmospheric humidity reaches a defined threshold:

controlling throttle valve ( 4 ) by signals from the temperature and humidity sensors to throttle the mass flow of refrigerant in the circuit upstream of the passenger compartment heat exchanger ( 5 ), in such a manner that the moisture contained in the air stream passing the passenger compartment heat exchanger ( 5 ) is at least substantially condensed at the passenger compartment heat exchanger ( 5 ), and the moisture which has already condensed at the heat exchanger ( 5 ) remains at the heat exchanger ( 5 ), and

heating the passenger compartment by a heat source which is outside the circuit ( 1 ) until the temperature in the passenger compartment exceeds an upper limit temperature of the predefined range.

2. The method as claimed in claim 1 , wherein said temperature range and atmospheric humidity threshold are determined based on the dewpoint temperature which leads to fogging of the windows.

3. The method as claimed in claim 1 , wherein said a heat source which is outside the circuit ( 1 ) includes a heating heat exchanger ( 24 ) which has heated engine coolant from an engine cooling circuit ( 12 ) flowing through it, and also has an air stream that is routed into the passenger compartment passing through it.

4. The method as claimed in claim 3 , comprising heating, prior to throttling the mass flow of refrigerant in the refrigerating circuit ( 1 ), both the refrigerant and the engine coolant by means of the compressor ( 2 ), which acts in the heat pump, of the refrigerating circuit ( 1 ), with heat being removed from the refrigerating circuit ( 1 ) via a countercurrent heat exchanger ( 23 ) and transferred to the engine coolant.

5. The method as claimed in claim 4 , wherein the heat is transferred only to the engine coolant of a first section ( 14 ) of the engine cooling circuit ( 12 ), which first section ( 14 ) includes a heating pump ( 22 ) and the heating heat exchanger ( 24 ), and wherein a second circuit section ( 13 ) of the engine cooling circuit ( 12 ), which includes the engine ( 16 ) and the radiator ( 17 ), are fluidically decoupled from the first circuit section ( 14 ).

6. The method as claimed in claim 1 , wherein during heating, the air-conditioning system is switched to recirculated air, the refrigerant releasing its heat in the counter-current heat exchanger ( 23 ) and being throttled in the throttle valve ( 4 ) to a pressure which correlates with a temperature such that the temperature at the surface of the passenger compartment heat exchanger ( 5 ) is below the dewpoint temperature which leads to fogging of the windows.

Assignments (8)