Pre-trip diagnostic methods for a temperature control unit

• US 6,996,997 B2
• Filed: 03/05/2003
• Issued: 02/14/2006
• Est. Priority Date: 03/05/2003
• Status: Expired due to Fees

• Current Assignee: Thermo King Corporation (Trane Technologies plc)
• Original Assignee: Thermo King Corporation (Trane Technologies plc)
• Inventors: Wiff, James W., Hanson, Jay. L., Carlson, Bill A.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US10/382,161
• Publication Number:
  US 20040172954A1
• Time in Patent Office: 1,077 Days
• Field of Search: 621/25, 621/26, 621/27, 621/29, 621/30, 621/31, 165/11.1, 165/11.2, 236/94
• US Class Current: 62/127
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/38 Failure diagnosis
• CPC Class Codes: F24F 11/49 ensuring correct operation, e.g. by trial operation or configuration checks
• CPC Class Codes: F25D 2700/12 Sensors measuring the inside temperature
• CPC Class Codes: F25D 29/003 for movable devices
• CPC Class Codes: G01K 15/00 Testing or calibrating of thermometers

Abstract

Methods of diagnosing a temperature control unit and methods of performing a diagnostic check on a temperature control unit. The methods generally include monitoring at least one function of the temperature control unit, storing information relating to the at least one monitored function, determining from the information relating to the at least one monitored function whether the unit has a malfunction. Some methods generally include setting a flag to one of a first setting and a second setting, the flag being set to the first setting if the unit has no malfunction and the flag being set to the second setting if the unit has at least one malfunction, and enabling the diagnostic check when the flag is set to the first setting. Some methods generally include enabling at least one of a first diagnostic check and a second diagnostic check on the unit, the first diagnostic check being enabled if the unit has no malfunction and the second diagnostic check being enabled whether the unit has no malfunction or at least one malfunction, wherein the first diagnostic check consumes a shorter period of time to successfully complete than the second diagnostic check.

Claims

1. A method of performing a diagnostic check on a temperature control unit, the method comprising:

initiating a first operation of the unit;

monitoring at least one function of the unit during the first operation;

storing information relating to the at least one monitored function of the unit from the first operation;

determining from the information relating to the at least one monitored function whether the unit has at least one malfunction during the first operation;

setting a flag to one of a first setting and a second setting during the first operation, the flag being set to the first setting if the unit has no malfunction during the first operation and the flag being set to the second setting if the unit has at least one malfunction during the first operation;

terminating the first operation of the unit;

enabling the diagnostic check after termination of the first operation when the flag is set to the first setting; and

enabling a second operation of the unit if the diagnostic check does not determine that the unit has a malfunction that prevents the diagnostic check from completing.

2. The method as claimed in claim 1, wherein the temperature control unit is a transport temperature control unit.

3. The method as claimed in claim 1, wherein the at least one function generates at least one alarm code, and wherein monitoring includes monitoring the at least one alarm code.

4. The method as claimed in claim 1, wherein the at least one function is a defrost cycle, and wherein monitoring includes monitoring the defrost cycle.

5. The method as claimed in claim 1, wherein the at least one function is a control sensor temperature of a control sensor, and wherein monitoring includes monitoring the at least one control sensor temperature of the control sensor and determining includes determining whether the control sensor temperature is within a predetermined range of a thermal setpoint, the unit not having a malfunction if the control sensor temperature is within the predetermined range of the thermal setpoint, the unit having at least one malfunction if the control sensor temperature is not within the predetermined range of the thermal setpoint.

6. The method as claimed in claim 5, wherein the control sensor is one of a return air temperature sensor and a discharge air temperature sensor, and the control sensor temperature is one of a return air temperature and discharge air temperature.

7. The method as claimed in claim 1, wherein storing includes storing a control sensor reference temperature of a control sensor and determining includes determining an appropriate temperature change and an appropriate time period based on the control sensor reference temperature, determining also includes determining whether the unit changes the control sensor temperature the appropriate temperature change within the appropriate time period, time unit having a malfunction if the control sensor temperature does not change the appropriate temperature change within the appropriate time period, and the unit not having a malfunction if the control sensor temperature changes the appropriate temperature change within the appropriate time period.

8. The method as claimed in claim 1, wherein the diagnostic check includes initiating a cooling check and monitoring a return air temperature, a discharge air temperature, and an ambient air temperature of a return air temperature sensor, discharge air temperature sensor, and an ambient air temperature sensor, respectively, alter the cooling check is initiated.

9. The method as claimed in claim 8, wherein the diagnostic check further includes determining a cooling temperature differential based on the lowest of the return air temperature, the discharge air temperature, and the ambient air temperature, the cooling temperature differential representing a temperature difference between the return air temperature and the discharge air temperature, wherein the diagnostic check further includes continuously monitoring the return air temperature via the return air temperature sensor and the discharge air temperature via the discharge air temperature sensor, determining a continuously monitored return air temperature and discharge air temperature differential with the continuously monitored return air temperature and discharge air temperature, and determining if the continuously monitored return air temperature and discharge air temperature differential is greater than or equal to the appropriate cooling temperature differential within a predetermined period of time, the unit having at least one malfunction if the continuously monitored return air temperature and discharge air temperature differential is not greater than or equal to the appropriate cooling temperature differential within the predetermined period of time, and the unit not having a malfunction if the continuously monitored return air temperature and discharge air temperature differential is greater than or equal to the appropriate cooling temperature differential within the predetermined period of time.

10. The method as claimed in claim 1, wherein the diagnostic check includes initiating a heating check and monitoring a return air temperature and a discharge air temperature with a return air temperature sensor and a discharge air temperature sensor.

11. The method as claimed in claim 10, wherein the diagnostic check further includes determining if the discharge air temperature is greater than the return air temperature by a predetermined amount within a period of time, the unit having at least one malfunction if the discharge air temperature is not greater than the return air temperature by the predetermined amount within the period of time, and the unit not having a malfunction if the discharge air temperature is greater than the return air by the predetermined amount within the period of time.

12. The method as claimed in claim 1, wherein the diagnostic check initiates a cooling check and a heating check.

13. The method as claimed in claim 12, wherein the diagnostic check passes when both the cooling check and the heating check pass.

14. The method as claimed in claim 1, wherein the diagnostic check only checks cooling and heating operations of the unit.

15. The method as claimed in claim 1, wherein enabling the diagnostic check includes enabling the diagnostic check only when the flag is set to the first setting.

16. The method as claimed in claim 1, wherein the diagnostic check is a first diagnostic check, the method further comprising enabling a second diagnostic check after termination of the first operation when the flag is set to either of the first setting and the second setting, the first diagnostic check consuming a shorter period of time to successfully complete than the second diagnostic check.

17. A method of diagnosing a temperature control unit, the method comprising:

initiating operation of the unit;

monitoring at least one function of the unit during operation of the unit;

storing information relating to the at least one monitored function of the unit from the operation of the unit;

determining from the information relating to the at least one function whether the unit has at least one malfunction during the operation of the unit;

terminating operation of the unit; and

enabling at least one of a first diagnostic check and a second diagnostic check on the unit after termination of operation of the unit, the first diagnostic check being enabled if the unit had no malfunction during operation of the unit and the second diagnostic check being enabled whether the unit had no malfunction or the unit had at least one malfunction during operation of the unit, wherein the first diagnostic check consumes a shorter period of time to successfully complete than the second diagnostic check.

18. The method as claimed in claim 17, wherein the temperature control unit is a transport temperature control unit.

19. The method as claimed in claim 17, further comprising setting a flag to one of a first setting and a second setting during operation of the unit, the flag being set to the first setting if the unit has no malfunction during operation of the unit and the flag being set to the second setting if the unit has at least one malfunction during operation of the unit.

20. The method as claimed in claim 19, wherein enabling includes enabling at least one of the first diagnostic check and the second diagnostic check, the first diagnostic check being enabled when the flag is set to the first setting and the second diagnostic check being enabled when the flag is set to either of the first setting and the second setting.

21. The method as claimed in claim 17, wherein the first diagnostic check includes a cooling check and a heating check.

22. The method as claimed in claim 21, wherein the first diagnostic check passes when both the cooling check and the heating check pass.

23. The method as claimed in claim 17, wherein the first diagnostic check only checks cooling and heating operations of the unit.

24. The method as claimed in claim 17, wherein the first diagnostic check checks cooling and heating operations of the unit and the second diagnostic check checks more than the cooling and heating operations of the unit.

25. The method as claimed in claim 17, further comprising terminating the one of the first diagnostic check and the second diagnostic check, and reinitiating operation of the unit after the termination of the one of the first diagnostic check and the second diagnostic check if the unit does not have a malfunction that prevented the one of the first diagnostic check and the second diagnostic check from successfully completing.

26. A method of diagnosing a temperature control unit, the method comprising:

initiating a first operation of the unit;

monitoring a control temperature sensor of the unit during the first operation;

storing a control sensor reference temperature of the control sensor from the first operation;

determining an appropriate temperature change and an appropriate time period based on the control sensor reference temperature;

determining whether the unit changes the control sensor temperature the appropriate temperature change within the appropriate time period, the unit having a malfunction if the control sensor temperature does not change the appropriate temperature change within the appropriate time period, and the unit not having a malfunction if the control sensor temperature changes the appropriate temperature change within the appropriate time period;

terminating the first operation of the unit;

enabling one of a first diagnostic check and a second diagnostic check after termination of the first operation of the unit, based on whether the unit had a malfunction during the first operation, wherein the first diagnostic check is enabled when the unit had no malfunction during the first operation and wherein the second diagnostic check is enabled whether the unit had no malfunction or at least one malfunction during the first operation, the first diagnostic check only checking cooling and heating operations of the unit and the second diagnostic check checking more than the cooling and heating operations of the unit;

initiating the one of the first diagnostic check and the second diagnostic check; and

initiating a second operation of the unit if the unit does not have a malfunction that prevented the one of the first diagnostic check and the second diagnostic check from successfully completing.

27. The method as claimed in claim 26, wherein the control sensor is one of a return air temperature sensor and a discharge air temperature sensor, and the control sensor temperature is one of a return air temperature and discharge air temperature.

28. The method as claimed in claim 26, wherein the temperature control unit is a transport temperature control unit.

29. The method as claimed in claim 26, further comprising setting a flag to one of a first setting and a second setting during the first operation of the unit, the flag being set to the first setting if the unit had no malfunction during the first operation of the unit and the flag being set to the second setting if the unit had at least one malfunction during the first operation of the unit, and wherein enabling includes enabling the first diagnostic check when the flag is set to the first setting and enabling the second diagnostic check when the flag is set to the second setting.

30. The method as claimed in claim 26, wherein the first diagnostic check passes when both the cooling and heating operations pass without a malfunction.