Air-conditioning system for a motor vehicle

• US 20020035843A1
• Filed: 06/26/2001
• Published: 03/28/2002
• Est. Priority Date: 07/25/2000
• Status: Active Grant

• Current Assignee: BEHR GmbH & Company KG (MAHLE-STIFTUNG GmbH)
• Original Assignee: BEHR GmbH & Company KG (MAHLE-STIFTUNG GmbH)
• Inventors: Kampf, Hans
• Granted Patent: US 6,449,974 B1
• Time in Patent Office: Days
• US Class Current: 62/231
• CPC Class Codes: B60H 1/00328 of the liquid-air type
• CPC Class Codes: B60H 1/00914 where the flow direction of the refrigerant does not change and there is a bypass of the condenser
• CPC Class Codes: B60H 1/00921 where the flow direction of the refrigerant does not change and there is an extra subcondenser, e.g. in an air duct
• CPC Class Codes: B60H 2001/00949 comprising additional heating/cooling sources, e.g. second evaporator
• CPC Class Codes: F25B 29/003 of the compression type system
• CPC Class Codes: F25B 41/20 Disposition of valves, e.g. of on-off valves or flow control valves expansion valves F25B41/31
• CPC Class Codes: F25B 5/00 Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity with cascade operation F25B7/00
• CPC Class Codes: F25B 5/04 arranged in series

Abstract

An air-conditioning system for a motor vehicle has a circuit (14) which is capable of being changed over from cooling to heating. The system has a heater (22), through which the air to be conditioned flows, a cooling heat exchanger (18) acting as an evaporator in the cooling mode, and an additional heat exchanger (20) capable of being selectively used for providing auxiliary heat in the heating mode. The additional heat exchanger can be advantageously utilized by operating it as an auxiliary cooling heat exchanger, acting as an evaporator, in the cooling mode.

Claims

1. An air-conditioning system for a motor vehicle, comprising:

a refrigerant source including a compressor for providing compressed refrigerant, and a first condenser;

a housing for routing air that is to be conditioned;

a first heat exchanger through which the air to be conditioned is capable of being selectively directed, positioned in said housing;

a first evaporator positioned in said housing upstream of the first heat exchanger, said first evaporator being connected to said refrigerant source;

a second heat exchanger positioned upstream of the first heat exchanger, said second heat exchanger being capable of being selectively connected to the refrigerant source; and

a control circuit for the air-conditioning system, said control circuit being capable of switching between (1) a cooling mode in which said first evaporator and optionally said second heat exchanger are provided with condensed refrigerant from the refrigerant source, whereby said second heat exchanger optionally functions as an evaporator, and (2) a heating mode in which said second heat exchanger is selectively provided with compressed refrigerant from the refrigerant source and functions as a condenser.

2. An air-conditioning system as claimed in claim 1, wherein the first evaporator and the second heat exchanger are connected to one another to form a heat exchanger block.

3. An air-conditioning system as claimed in claim 1, wherein the control circuit in the cooling mode selectively disables the second heat exchanger at a predetermined low cooling demand level.

4. An air-conditioning system as claimed in claim 1, wherein the first evaporator and the second heat exchanger are connected in series on the air-side.

5. An air-conditioning system as claimed in claim 1, wherein the refrigerant source further comprises a second evaporator positioned outside of said housing to receive refrigerant from said second heat exchanger.

6. An air-conditioning system as claimed in claim 1, further comprising a blower positioned in the housing.

7. An air-conditioning system as claimed in claim 1, wherein said control circuit further comprises a control element for permitting lapse of a predetermined minimum period of time before supplying said second heat exchanger with compressed refrigerant when the control system is switched from said cooling mode, in which refrigerant is supplied to said second heat exchanger, to said heating mode.

8. A method for operating an air-conditioning system as claimed in claim 1, comprising:

operating said system in said cooling mode, wherein refrigerant is supplied to said second heat exchanger;

switching said system to said heating mode; and

after permitting lapse of a predetermined minimum period of time, supplying said second heat exchanger with compressed refrigerant.