Vehicle configured to prevent oil entrapment within refrigerant system and corresponding method

Patent metadata

Field	Value
Publication number	US-10933718-B2
Application number	US-201916413649-A
Country	US
Kind code	B2
Filing date	May 16, 2019
Priority date	May 16, 2019
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

This disclosure relates to a vehicle configured to prevent oil entrapment within a refrigerant system of the vehicle. This disclosure also relates to a corresponding method. An example vehicle includes a refrigerant system configured to circulate fluid including a mixture of refrigerant and oil relative to an evaporator, a controller, and an electronic expansion valve upstream of the evaporator. The electronic expansion valve is responsive to instructions from the controller, and the controller is configured to instruct the electronic expansion valve to open to prevent entrapment of oil within the evaporator or refrigerant lines.

First claim

The invention claimed is:

1. A vehicle, comprising:
a refrigerant system configured to circulate fluid relative to a first evaporator and a second evaporator arranged in parallel with the first evaporator, the fluid including a mixture of refrigerant and oil;
a controller;
a compressor responsive to instructions from the controller;
a first electronic expansion valve upstream of the first evaporator and responsive to instructions from the controller; and
a second electronic expansion valve upstream of the second evaporator and responsive to instructions from the controller, wherein the controller is configured to instruct the first and second electronic expansion valves to open based on an oil entrapment prevention strategy in series such that when one of the first and second electronic expansion valves is opened based the oil entrapment prevention strategy the other of the first and second electronic expansion valves is controlled based on a normal control strategy, and wherein, when either of the first or second electronic expansion valves is opened based on the oil entrapment prevention strategy, the controller is configured to instruct the compressor to continue operating.

2. The vehicle as recited in claim 1 , wherein, when either of the first or second electronic expansion valves is opened based on the oil entrapment prevention strategy, the controller is configured to instruct the compressor to operate above a minimum threshold speed.

3. The vehicle as recited in claim 2 , wherein the controller runs the oil entrapment prevention strategy by first issuing instructions to open the first electronic expansion valve based on the oil entrapment prevention strategy while the second electronic expansion valve is controlled based on the normal control strategy, and by next issuing instructions to open the second electronic expansion valve based on the oil entrapment prevention strategy while the first electronic expansion valve is controlled based on the normal control strategy.

4. The vehicle as recited in claim 1 , wherein:
the refrigerant system includes at least one sensor,
the controller is configured to interpret signals from the at least one sensor to determine whether fluid exiting the first evaporator and the second evaporator is superheated,
the controller runs the oil entrapment prevention strategy by first issuing instructions to open the first electronic expansion valve based on the oil entrapment prevention strategy until the fluid exiting the first evaporator is superheated, and by next issuing instructions to open the second electronic expansion valve based on the oil entrapment prevention strategy until the fluid exiting the second evaporator is superheated.

5. The vehicle as recited in claim 4 , wherein:
the at least one sensor includes a first temperature sensor and a first pressure sensor adjacent the first evaporator, and
the at least one sensor further includes a second temperature sensor and a second pressure sensor adjacent the second evaporator.

6. The vehicle as recited in claim 1 , wherein the first evaporator is configured to thermally condition a front section of a vehicle cabin and the second evaporator is configured to thermally condition a rear section of the vehicle cabin.

7. The vehicle as recited in claim 6 , wherein:
the refrigerant system includes a third evaporator in parallel with both the first evaporator and the second evaporator, and
the third evaporator is configured to thermally condition a battery pack of the vehicle.

8. The vehicle as recited in claim 7 , wherein:
the refrigerant system includes a third electronic expansion valve upstream of the third evaporator,
when the controller instructs either the first or second electronic expansion valves to open based on the oil entrapment prevention strategy, the third electronic expansion valve is controlled based on the normal control strategy,
the controller is configured to instruct the third electronic expansion valve to open based on the oil entrapment prevention strategy while the first and second electronic expansion valves are controlled based on the normal control strategy, and
when the third electronic expansion valve is opened based on the oil entrapment strategy, the controller is configured to instruct the compressor to continue operating.

9. A method, comprising:
opening a first electronic expansion valve upstream of a first evaporator of a vehicle refrigerant system according to an oil entrapment prevention strategy to prevent entrapment of oil within the first evaporator while controlling a second electronic expansion valve upstream of a second evaporator of the vehicle refrigerant system based on a normal control strategy;
after the step of opening the first electronic expansion valve according to the oil entrapment prevention strategy, opening the second electronic expansion valve according to the oil entrapment prevention strategy to prevent entrapment of oil within the second evaporator while controlling the first electronic expansion valve based on the normal control strategy; and
operating a compressor of the vehicle refrigerant system above a minimum threshold speed when either of the first or second electronic expansion valves is opened based on the oil entrapment prevention strategy.

10. The method as recited in claim 9 , wherein the compressor circulates fluid within the vehicle refrigerant system, the fluid including oil and refrigerant.

11. The method as recited in claim 9 , wherein the opening and operating steps are performed for a predefined period of time and at predefined intervals.

12. The method as recited in claim 11 , wherein the opening and operating steps are performed during the predefined period of time regardless of whether the normal control strategy would otherwise require opening either of the first or second electronic expansion valves or operating the compressor above the minimum threshold speed during the predefined period of time.

13. The method as recited in claim 9 , wherein:
the step of opening the first electronic expansion valve according to the oil entrapment prevention strategy lasts until fluid exiting the first evaporator is superheated, and
the step of opening the second electronic expansion valve according to the oil entrapment prevention strategy lasts until fluid exiting the second evaporator is superheated.

14. The method as recited in claim 9 , wherein the first evaporator is configured to thermally condition a front section of a vehicle cabin and a second evaporator is configured to thermally condition a rear section of the vehicle cabin.

15. The method as recited in claim 9 , wherein:
the step of opening the first electronic expansion valve according to the oil entrapment prevention strategy lasts for between 15 and 30 seconds, and
the step of opening the second electronic expansion valve according to the oil entrapment prevention strategy lasts for between 15 and 30 seconds.

Assignees

• Ford Global Tech Llc

Inventors

• Smith Mark G
• Blatchley Timothy Noah

Classifications

• B60H2001/3252

  of the refrigerant at an evaporating unit · CPC title

• H05K7/20881

  Liquid coolant with phase change · CPC title

• B60H1/3225

  characterised by safety arrangements, e.g. compressor anti-seizure means or by signalling devices · CPC title

• F25B5/02

  arranged in parallel · CPC title

• B60H1/3214

  for improving the lubrication of a refrigerant compressor in a vehicle · CPC title