Method and apparatus for controlling a combined heating and cooling vapor compression system

Patent metadata

Field	Value
Publication number	US-9452659-B2
Application number	US-201213731247-A
Country	US
Kind code	B2
Filing date	Dec 31, 2012
Priority date	Dec 31, 2012
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

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.

First claim

The invention claimed is:

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, wherein the second control action includes the steps of:
signaling a first flow control valve to occupy a second position to route a refrigerant in the vapor compression system through a second heat exchanger;
signaling a second flow control valve to occupy an open position, such that the refrigerant flows 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 a heat pump performance of the vapor compression system, when the compressor is operating at a predetermined operating speed, such that evaluating the heat pump performance of the vapor compression system further includes returning a heat pump performance result, wherein the heat pump performance 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 a coolant through an RESS chiller and adjusting an output of an electric heater to obtain a heat pump performance result which indicates the first condition, such that adjusting the flow of the 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:
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 the refrigerant is directed to each of the first heat exchanger and the second heat exchanger simultaneously, such that the vapor compression system operates 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; 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 the first flow control valve to occupy a first position to route the refrigerant in the vapor compression system through the first heat exchanger, such that the refrigerant dissipates heat to an ambient environment;
signaling the second flow control valve to occupy the open position, such that the refrigerant flows through each of the cabin evaporator and the RESS chiller simultaneously, to cool the cabin and to cool the RESS chiller; and
operating the compressor at a predetermined speed to circulate the refrigerant throughout the vapor compression system.

3. The method of claim 2 wherein operating the compressor to circulate the refrigerant through the vapor compression system further comprises the steps of:
setting the predetermined operating speed for the compressor;
determining a target evaporator air temperature of the cabin evaporator by evaluating a humidity level of the cabin and a 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.

4. The method of claim 3 wherein the target evaporator air temperature ranges from about 2° C. to about 10° C.

5. The method of claim 1 wherein the flow rate of the coolant through the RESS chiller is increased in order to scavenge heat from the RESS chiller until the flow rate of coolant through the RESS chiller reaches a predetermined maximum; and wherein the electric heater is powered on when the flow rate of the coolant through the RESS chiller reaches the predetermined maximum, such that the heat pump performance result is adjusted from a result indicating the second condition to a result indicating the first condition.

6. The method of claim 1 wherein reducing the output of the electric heater, reducing flow of the refrigerant 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.

7. The method of claim 1 wherein the third control action further comprises:
signaling the first flow control valve to occupy the second position to route the refrigerant in the vapor compression system through the second heat exchanger;
signaling the second flow control valve to occupy a closed position, such that the refrigerant flows through the RESS chiller and the refrigerant is blocked 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 refrigerant expelled from 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.

8. The method of claim 7 wherein the actual discharge pressure is greater than the target discharge pressure, the method further comprising the steps of:
increasing flow of the coolant through the second heat exchanger until one of a flow rate of the coolant through the second heat exchanger reaches a predetermined maximum flow rate and the target discharge pressure is reached; and
reducing the compressor speed, when the flow rate of the coolant through the second heat exchanger reaches the predetermined maximum flow rate until the target discharge pressure is reached.

9. The method of claim 7 wherein the actual discharge pressure is less than the target discharge pressure, the method further comprising the step of:
determining whether a compressor suction pressure is one of greater than a predetermined suction durability limit of the compressor and less than the predetermined suction durability limit of the compressor.

10. The method of claim 9 wherein the compressor suction pressure is less than the predetermined suction 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 rate of the coolant through the RESS chiller, while maintaining the target discharge pressure, when the compressor speed is at the predetermined minimum value.

11. The method of claim 9 wherein the compressor suction pressure is greater than the predetermined suction durability limit of the compressor, the method further comprising the steps of:
increasing the compressor speed, to increase the actual discharge pressure to the

Assignees

• Gm Global Tech Operations Llc

Inventors

• Styles Bryan M
• Nemesh Mark D

Classifications

• B60H1/00899

  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 title

• B60H1/00807

  the input being a specific way of measuring or calculating an air or coolant temperature · CPC title

• B60H2001/00949

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

• B60H2001/00307

  Component temperature regulation using a liquid flow · CPC title

• B60H1/00278 Primary

  for the battery · CPC title