Method for operating an air conditioner for a motor vehicle

Patent metadata

Field	Value
Publication number	US-9656535-B2
Application number	US-201314029433-A
Country	US
Kind code	B2
Filing date	Sep 17, 2013
Priority date	Sep 17, 2012
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

The invention relates to a method for operating an air conditioner ( 1 ) for treating the air of a passenger compartment of a motor vehicle. The air conditioner ( 1 ) exhibits a refrigerant circuit ( 2 ) configured for a combined cooling unit and heat-pump mode and for a post-heating mode. In the heat-pump mode with a first and a second heat source, two heat sources differing from each other can be used. A temperature of the first heat source, a temperature of the second heat source, and a regulation characteristic number and a maximum pressure are taken into account in the refrigerant circuit ( 2 ) for operating the air conditioner ( 1 ) in a heat-pump mode. The invention additionally relates to a method for switching between the two heat-pump modes.

First claim

What is claimed is:

1. A method of operating an air conditioner for treating air of a passenger compartment of a motor vehicle, the method comprising the steps of:
providing the air conditioner, wherein the air conditioner includes a refrigerant circuit configured for a combined cooling unit mode and heat-pump mode and for a post-heating mode, and wherein the air conditioner has a first heat source and a second heat source when in the heat-pump mode;
determining a temperature of the first heat source;
determining a temperature of the second heat source;
determining a regulation characteristic number, wherein the regulation characteristic number is determined from a deviation of a target status of the air to be fed into the passenger compartment from a de facto status of the air to be fed into the passenger compartment;
determining a maximum pressure within the refrigerant circuit; and
changing a mode of operation of the air conditioner based on the determination of at least one of the temperature of the first heat source, the temperature of the second heat source, the regulation characteristic number, and the maximum pressure within the refrigerant circuit,
wherein the air conditioner operating in the heat-pump mode is configured to be operable in at least one of a first heat-pump mode and a second heat-pump mode, wherein in the first heat-pump mode at least the first heat source is used and in the second heat-pump mode at least the second heat source is used, wherein a method for changing between the first heat-pump mode and the second heat-pump mode comprises the steps of:
operating the air conditioner in the first heat-pump mode;
comparing the temperature of the first heat source with a first limit value;
wherein:
1) if the temperature of the first heat source reaches or exceeds the first limit value, a determination is made whether a maximum heating performance setting on an operating device of the air condition is activated, wherein:
i) if the maximum heating performance setting is not activated, operation in the first heat-pump mode is maintained;
ii) if the maximum heating performance setting is activated, the temperature of the second heat source is compared with a second limit value, wherein:
 a) upon the temperature of the second heat source reaching or exceeding the second limit value, operation in the first heat-pump mode is maintained;
 b) if the temperature of the second heat source falls short of the second limit value, operation is changed to the second heat-pump mode;

2) if the temperature of the first heat source falls short of the first limit value, the temperature of the second heat source is compared with a sixth limit value, wherein:
i) if the temperature of the second heat source reaches or falls short of the sixth limit value, operation in the first heat-pump mode is maintained;
ii) if the temperature of the second heat source exceeds the sixth limit value, the temperature of the second heat source is compared with the second limit value, wherein:
 a) if the temperature of the second heat source reaches or exceeds the second limit value, operation is maintained in the first heat-pump mode;
 b) if the second limit value is fallen short of, the operation changes to the second heat-pump mode.

2. The method according to claim 1 , further comprising the steps of:
operating the air conditioner in the heat-pump mode;
comparing the temperature of the first heat source with a first limit value, wherein upon the temperature of the first heat source reaching or exceeding the first limit value the refrigerant circuit is not operated in the heat-pump mode;
comparing the temperature of the second heat source with a second limit value, wherein upon the temperature of the second heat source reaching or exceeding the second limit value the refrigerant circuit is not operated in the heat-pump mode;
comparing the regulation characteristic number with a third limit value, wherein upon the regulation characteristic number reaching or falling short of the third limit value the refrigerant circuit is not operated in the heat-pump mode; and
comparing the maximum pressure in the refrigerant circuit with a fifth limit value, wherein upon the maximum pressure reaching or exceeding the fifth limit value the refrigerant circuit is not operated in the heat-pump mode.

3. The method according to claim 2 , further comprising the step of determining and comparing a temperature of the air in the passenger compartment with a fourth limit value, wherein upon the temperature of the air in the passenger compartment reaching or exceeding the fourth limit value the refrigerant circuit is not operated in the heat-pump mode.

4. The method according to claim 2 , wherein:
the first limit value of the first heat source is in the range of about 0° C. to 20° C.;
the second limit value of the second heat source is in the range of about 30° C. to 100° C.;
the third limit value of the regulation characteristic number exhibits a value at which a desired temperature of the air is reached in the passenger compartment and it is not necessary to operate the air conditioner in a heat-pump mode to obtain the desired temperature of the air in the passenger compartment; and
the fifth limit value of maximum pressure in the refrigerant circuit is in the range of about 18 bar to 32 bar.

5. The method according to claim 1 , wherein:
the first limit value of the first heat source is in the range of about −10° C. to +5° C.;
the second limit value of the second heat source is in the range of about 40° C. to 70° C.; and
the sixth limit value of the second heat source is in the range of about 0° C. to 20° C.

6. The method according to claim 1 , wherein the operation of the air conditioner is changed to the second heat-pump mode, the method further comprising the steps of:
comparing the regulation characteristic number with a third limit value, wherein:
1) if the regulation characteristic number exceeds the third limit value, the operation is maintained in the second heat-pump mode;
2) if the regulation characteristic number reaches or falls short of the third limit value, the operation is changed into the first heat-pump mode; and

comparing the maximum pressure in the refrigerant circuit with a fifth limit value, wherein:
1) if the maximum pressure in the refrigerant circuit reaches or falls short of the fifth limit value, the operation is maintained in the second heat-pump mode;
2) if the maximum pressure in the refrigerant circuit exceeds the fifth limit value, operation is changed to the first heat-pump mode.

7. The method according to claim 6 , wherein:
the third limit value of the regulation characteristic number is a value which identifies a temperature below the desired temperature in the passenger compartment; and
the fifth limit value of the maximum pressure in the refrigerant circuit lies in a range between about 2 bar and 16 bar.

Assignees

• Visteon Global Tech Inc
• Hanon Systems

Inventors

• Heyl Peter
• Schroeder Dirk
• Hammer Hans
• Bodewig Jorg

Classifications

• B60H2001/00949

  comprising additional heating/cooling sources, e.g. second evaporator · CPC title

• B60H1/00878 Primary

  the components being temperature regulating devices · CPC title

• B60H1/00921 Primary

  where the flow direction of the refrigerant does not change and there is an extra subcondenser, e.g. in an air duct · CPC title