METHOD AND APPARATUS FOR CONTROLLING A COMBINED HEATING AND COOLING VAPOR COMPRESSION SYSTEM

• US 20140182832A1
• Filed: 12/31/2012
• Published: 07/03/2014
• Est. Priority Date: 12/31/2012
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Styles, Bryan M., Nemesh, Mark D.
• Granted Patent: US 9,452,659 B2
• Time in Patent Office: Days
• US Class Current: 165/202
• CPC Class Codes: B60H 1/00278 for the battery arrangement of batteries B60R16/04
• CPC Class Codes: B60H 1/00807 the input being a specific way of measuring or calculating an air or coolant temperature
• CPC Class Codes: B60H 1/00899 Controlling the flow of liquid in a heat pump system controlling the properties of the refrigerant liquid, e.g. pressure or temperature, B60H1/3204
• CPC Class Codes: B60H 2001/00307 Component temperature regulation using a liquid flow
• CPC Class Codes: B60H 2001/00949 comprising additional heating/cooling sources, e.g. second evaporator

Abstract

A system and method for controlling a combined heating and cooling vapor compression system are provided. The apparatus may be a vehicle and may include a cabin, a vehicle battery, a Rechargeable Energy Storage System (RESS), and a vapor-compression system, having at least one controller, operable in a variety of modes selectable to facilitate cooling, heating, and dehumidification of the vehicle cabin. The method may include steps to adjust evaporator air temperature to control comfort, fogging and smell in the cabin by adjusting the compressor speed; regulate heat pump performance by adjusting the output of an electric heater and adjusting the flow of coolant through the RESS chiller; and evaluating and optimizing the discharge pressure and suction pressure of the compressor by adjusting the compressor speed and adjusting the coolant flow through the RESS chiller.

Claims

1. A method for controlling a combined heating and cooling vapor compression system for use in a vehicle, the method comprising the steps of:

detecting one of a first precondition, a second precondition, and a third precondition, with at least one controller, wherein the first precondition is a demand for cooling in a vehicle cabin, the second precondition is a demand for heating and dehumidification in the vehicle cabin, and the third precondition is a demand for heating only in the vehicle cabin;

executing a first control action, with the at least one controller, when the first precondition is detected, to allow the vapor compression system to operate in a first mode wherein cooling of the cabin is demanded;

executing a second control action, with the at least one controller, when the second precondition is detected, to allow the vapor compression system to operate in a second mode, wherein each of heating of the cabin and dehumidification of the cabin are demanded; and

executing a third control action, with the at least one controller, when the third precondition is detected, to allow the vapor compression system to operate in a third mode, wherein only heating of the cabin is demanded.

2. The method of claim 1 wherein the first control action comprises the steps of:

signaling a first flow control valve to occupy a first position to route the flow of refrigerant in the vapor compression system through a first heat exchanger and allowing the refrigerant to dissipate heat to an ambient environment;

signaling a second flow control valve to occupy an open position, allowing refrigerant to flow through each of a cabin evaporator and an RESS chiller simultaneously, to cool the cabin and to cool the RESS chiller; and

operating a compressor at a predetermined speed to circulate refrigerant throughout the vapor compression system.

3. The method of claim 1 wherein the second control action comprises the steps of:

signaling a first flow control valve to occupy a second position to route the flow of refrigerant in the vapor compression system through a second heat exchanger, prohibiting the refrigerant from dissipating heat to an ambient environment;

signaling a second flow control valve to occupy an open position, allowing refrigerant to flow through each of a cabin evaporator and an RESS chiller simultaneously, to cool the RESS chiller and to cool and dehumidify the cabin;

operating a compressor to circulate the refrigerant through the vapor compression system; and

evaluating the heat pump performance of the vapor compression system, when operating the compressor at a predetermined speed.

4. The method of claim 3 wherein operating a compressor further comprises the steps of:

setting a predetermined operating speed for the compressor;

determining a target evaporator air temperature of the cabin evaporator by evaluating the humidity level and the temperature of the cabin;

calculating a target compressor speed based on the target evaporator air temperature; and

adjusting the compressor speed to the target compressor speed.

5. The method of claim 4 wherein the target evaporator air temperature ranges from about 2°

C. to about 10°

C.

6. The method of claim 3 wherein evaluating the heat pump performance of the vapor compression system further comprises the steps of:

returning a heat pump performance result, wherein the result indicates a heat pump performance resulting in one of a first condition, a second condition, and a third condition.

7. The method of claim 6 further including the step of:

adjusting the flow of coolant through an RESS chiller and adjusting the output of an electric heater to obtain a heat pump performance result which indicates the first condition.

8. The method of claim 7 wherein the flow of coolant through the RESS chiller is increased in order to scavenge heat from the RESS chiller until the flow of coolant through the RESS chiller reaches a predetermined maximum;

and wherein the electric heater is powered on if the coolant flow through the RESS chiller is at the predetermined maximum, to alter the heat pump performance result from a result indicating the second condition to a result indicating the first condition.

9. The method of claim 7 wherein adjusting the flow of coolant through an RESS chiller and adjusting the output of an electric heater to obtain a heat pump performance result which indicates the first condition further includes the steps of:

reducing the output of the electric heater;

reducing coolant flow through the RESS chiller;

signaling the first control valve to occupy a third position, wherein refrigerant is directed to each of the first heat exchanger and the second heat exchanger simultaneously and allowing the vapor compression system to operate in a fourth mode; and

adjusting an air mix door to reduce the amount of air allowed to flow across the heater and into the cabin.

10. The method of claim 9 wherein reducing the output of the heater, reducing refrigerant flow through the RESS chiller, signaling the first control valve to occupy a third position, and adjusting an air mix door alter the heat pump performance from a result indicating the third condition to a result indicating the first condition.

11. The method of claim 1 wherein the third control action further comprises:

signaling a first flow control valve to occupy a second position to route the flow of refrigerant in the vapor compression system through a second heat exchanger and prohibiting the refrigerant from dissipating heat to an ambient environment;

signaling a second flow control valve to occupy a closed position, allowing refrigerant to flow through an RESS chiller but blocking the refrigerant from flowing through a cabin evaporator;

operating a compressor to circulate the refrigerant through the vapor compression system;

evaluating the actual discharge pressure of the compressor using a high-side pressure sensor;

determining a target discharge pressure to yield a predetermined refrigerant temperature; and

comparing the actual discharge pressure and the target discharge pressure.

12. The method of claim 11 wherein the actual discharge pressure is greater than the target discharge pressure, the method further comprising the steps of:

increasing flow of one of coolant and air through the second heat exchanger until the flow rate throughout the second heat exchanger reaches a predetermined maximum or the target discharge pressure is reached; and

reducing the compressor speed, when the flow rate through the second heat exchanger is at the predetermined maximum until the target discharge pressure is reached.

13. The method of claim 11 wherein the actual discharge pressure is less than the target discharge pressure, the method further comprising the step of:

determining whether the compressor suction pressure is greater than or less than a predetermined durability limit of the compressor.

14. The method of claim 13 wherein the suction pressure is less than the predetermined durability limit of the compressor, the method further comprising the steps of:

reducing the compressor speed until the compressor speed reaches a predetermined minimum value; and

increasing the flow of coolant through the RESS chiller, while maintaining the discharge pressure, when the compressor speed is at the predetermined minimum value.

15. The method of claim 13 wherein the suction pressure is greater than the predetermined durability limit of the compressor, the method further comprising the steps of:

increasing the compressor speed, to increase the actual discharge pressure to the target discharge pressure, until the compressor reaches a predetermined maximum speed; and

increasing the flow rate of the coolant through the RESS chiller, when the compressor is at the predetermined maximum speed, to increase the actual discharge pressure to the target discharge pressure.

16. The method of claim 11 wherein the predetermined suction durability limit of the compressor is from about 0.05 MPaA to about 0.20 MPaA.

17. A vehicle comprising:

a cabin;

a vehicle battery configured to provide a power source for the vehicle;

a Rechargeable Energy Storage System (RESS) configured to act as an evaporator in heat exchange relation with a refrigerant and air surrounding the vehicle battery;

a vapor-compression system operable in one of a first mode to facilitate cooling of the vehicle cabin, a second mode to facilitate heating and dehumidification of the vehicle cabin, a third mode to facilitate heating of the vehicle cabin, and a fourth mode wherein the vapor compression system provides heating and cooling to the vehicle cabin simultaneously, wherein the vapor compression system includes;

a compressor configured to compress refrigerant flowing through the vapor compression system;

a high-side pressure sensor configured to monitor the pressure of the refrigerant exiting the compressor;

a first heat exchanger in heat exchange relation with the refrigerant and the ambient environment;

a second heat exchanger in heat exchange relation with the refrigerant flowing through the second heat exchanger and one of the air flowing across the second heat exchanger and a coolant flowing through the second heat exchanger;

a first flow control valve configured to occupy one of a first position to allow the vapor compression system to operate in the first mode, a second position to allow the vapor compression system to operate in one of the second mode and the third mode, and a third position to allow the vapor compression system to operate in the fourth mode;

a second flow control valve configured to occupy one of an open position when the vapor compression system is operating in one of the first mode, the second mode, and the fourth mode and a closed position, when the vapor compression system is operating in the third mode;

a cabin evaporator in heat exchange relation with the refrigerant and the air flowing into the cabin;

an electric heater configured to provide heat to the air flowing across the cabin evaporator and into the passenger compartment;

at least one controller in electrical communication with the vapor compression system; and

wherein the controller is configured for;

detecting one of a first precondition, a second precondition, and a third precondition, with at least one controller, wherein the first precondition is a need for cooling in a vehicle cabin, the second precondition is a need for heating and dehumidification in the vehicle cabin, and the third precondition is a need for heating only in the vehicle cabin;

executing a first control action, with the at least one controller, when the first precondition is detected, to allow the vapor compression system to operate in a first mode wherein cooling of the cabin is needed;

executing a second control action, with the at least one controller, when the second precondition is detected, to allow the vapor compression system to operate in a second mode, wherein each of heating of the cabin and dehumidification of the cabin are needed; and

executing a third control action, with the at least one controller, when the third precondition is detected, to allow the vapor compression system to operate in a third mode, wherein only heating of the cabin is needed.

18. The vehicle of claim 17 wherein the second control action may further include:

signaling the first flow control valve to occupy a second position to route the flow of refrigerant in the vapor compression system through the second heat exchanger, prohibiting the refrigerant from dissipating heat to an ambient environment;

signaling the second flow control valve to occupy an open position, allowing refrigerant to flow through each of the cabin evaporator and the RESS chiller simultaneously, to cool the RESS chiller and to cool and dehumidify the cabin;

operating the compressor to circulate the refrigerant through the vapor compression system;

evaluating the heat pump performance of the vapor compression system, when operating the compressor at a predetermined speed;

returning a heat pump performance result, wherein the result indicates a heat pump performance resulting in one of a first condition, a second condition, and a third condition; and

adjusting the flow of coolant through the RESS chiller and adjusting the output of the electric heater to obtain a heat pump performance result which indicates the first condition.

19. The method of claim 17 wherein the third control action further comprises:

signaling the first flow control valve to occupy a second position to route the flow of refrigerant in the vapor compression system through the second heat exchanger and prohibiting the refrigerant from dissipating heat to the ambient environment;

signaling the second flow control valve to occupy a closed position, allowing refrigerant to flow through the RESS chiller but blocking the refrigerant from flowing through the cabin evaporator;

operating the compressor to circulate the refrigerant through the vapor compression system;

evaluating an actual discharge pressure of the compressor using the high-side pressure sensor;

determining a target discharge pressure to yield a predetermined refrigerant temperature;

comparing the actual discharge pressure and the target discharge pressure; and

adjusting the flow of refrigerant through the second heat exchanger and adjusting the speed of the compressor to yield an actual discharge pressure equal to the target discharge pressure.