Method for Monitoring Performance of the Lubricant Cooler in Aircraft Auxiliary Power Unit

• US 20160230659A1
• Filed: 07/23/2014
• Published: 08/11/2016
• Est. Priority Date: 07/24/2013
• Status: Active Grant

• Current Assignee: Air China Limited
• Original Assignee: Air China Limited
• Inventors: ZHANG, Hailong, WANG, Bingzheng, GU, Zhuping, DING, Huifeng, ZHENG, Fengliang, WU, Jiaju, CHEN, Lei, HUANG, Lei
• Granted Patent: US 9,689,311 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B64D 33/08 of power plant cooling systems cooling of internal-combustion engines per se F01P; cooling of gas-turbine plants or jet-propulsion plants per se F02C, F02K
• CPC Class Codes: B64D 41/00 Power installations for auxiliary purposes
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F01M 5/002 Cooling
• CPC Class Codes: F02C 7/14 of fluids in the plant , e.g. lubricant or fuel F02C7/185 takes precedence
• CPC Class Codes: F05D 2220/50 for auxiliary power units (APU's)
• CPC Class Codes: F05D 2260/80 Diagnostics
• CPC Class Codes: F05D 2260/98 Lubrication
• CPC Class Codes: G01M 15/14 Testing gas-turbine engines or jet-propulsion engines
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

The present invention relates to a method for detecting performance of the lubricant cooler in aircraft auxiliary power unit APU, comprising: acquiring APU-related messages within a time period; obtaining the operation parameters of the APU lubricant cooler, the operation parameters comprise: lubricant temperature OT and load compressor inlet temperature LCIT; the revised lubricant temperature OT is obtained by the following formula: the revised lubricant temperature=lubricant temperature OTA−the load compressor inlet temperature LCIT; determining the performance of the APU lubricant cooler is in stable phase, decline phase or malfunction phase according to the change trend of the revised lubricant temperature OT with respect to time.

Claims

1. A method for monitoring the performance of an aircraft auxiliary power unit APU lubricant cooler, comprising:

acquiring APU messages within a time period;

obtaining the operation parameters of the APU lubricant cooler according to the APU messages, the operation parameters including lubricant temperature OTA and load compressor inlet temperature LCIT;

obtaining the revised lubricant temperature OT through the following formula;

revised lubricant temperature OT=lubricant temperature OTA−

load compressor inlet temperature LCIT; and

determining whether the performance of the APU lubricant cooler is in stable phase, decline phase or malfunction phase according to the change trend of the revised lubricant temperature OT with respect to time.

2. The method of claim 1, wherein the step for determining the performance of the APU lubricant cooler is in stable phase, decline phase or malfunction phase comprises:

in response to the change trend is less than the threshold value of decline, determining the performance of the APU lubricant cooler is in stable phase;

in response to the change trend is greater than the threshold value of decline and less than the threshold value of malfunction, determining the performance of the APU lubricant cooler is in decline phase; and

in response to the change trend is greater than the threshold value of malfunction, determining the performance of the APU lubricant cooler is in malfunction phase.

3. The method of claim 2, further comprising:

determining the stable change trend of the revised lubricant temperature OT with respect to time when the APU lubricant cooler is in stable phase;

wherein, the threshold value of the decline phase is around 1.5-2.5 times than the stable change trend, and the threshold value of malfunction is around 5-7 times than the stable change trend.

4. The method of claim 2, wherein, the decline phase further comprises serious decline phase, and the threshold value of serious decline is between the threshold values of the decline and malfunction, response to the change trend is greater than the threshold value of the serious decline and less than the threshold value of malfunction, determining the performance of the APU lubricant cooler is in serious decline phase;

wherein the method further comprises;

determining the stable change trend of the revised lubricant temperature OT with respect to time when the APU oil lube cooler is in stable phase;

wherein, the threshold value of the serious decline is around 2.5-5 times than the stable change trend.

5. The method of claim 1, further comprising:

the time is time since installation TSR of APU.

6. The method of claim 1, wherein the time period is about 5-10 days.

7. The method of claim 1, wherein about 20-30 APU messages are obtained within the time period.

8. The method of claim 1, wherein the APU messages are triggered to obtain the operation parameters when the APU load is at its peak.

9. The method of claim 1, wherein a plurality of the APU messages are triggered to obtain the operation parameters in the same APU load.

10. The method of claim 1, further comprising:

response to the lubricant temperature OTA exceeding the first threshold, issuing the warning signal.

11. The method of claim 1, further comprising:

response to the revised lubricant temperature OT exceeding the second threshold, issuing the warning signal.

12. The method of claim 1, further comprising:

calculating the average value AVG and the deviation index δ

of the revised lubricant temperature OT within the time period;

determining the revised lubricant temperature OT_next obtained according to the next message related to APU; and

response to OT_next is greater than AVG+nδ

or less than AVG−

nδ

, determining whether the revised lubricant temperature OT_next+1 obtained according to the further next message related to APU is equally greater than AVG+nδ

or less than AVG−

nδ

;

response to the revised lubricant temperature obtained according to the message related to APU is equally greater than AVG+nδ

or less than AVG−

nδ

continuously and exceeding the predetermined number Z, issuing the warning;

wherein n is 2-5 and Z is 3-5.

13. The method of claim 12, response to the revised lubricant temperature obtained according to the message related to APU is greater than AVG+nδ

or less than AVG−

nδ

, recalculating the average value AVG and deviation index δ

of the revised lubricant temperature OT.

14. The method of claim 12, response to the revised lubricant temperature obtained according to the message related to APU is equally greater than AVG+nδ

or less than AVG−

nδ

continuously and exceeding the predetermined number Z, recalculating the average value AVG and deviation index δ

of the revised lubricant temperature OT.

15. The method of claim 12, wherein the deviation index δ

is standard deviation.

16. The method of claim 12, wherein the value of n is 2 or 3.

17. The method of claim 12, wherein the value of Z is 3.

18. The method of claim 12, further comprising:

in response to the revised lubricant temperature obtained according to the message related to APU is greater than AVG+nδ

continuously and exceeding the predetermined number Z, issuing the warning of lubricant cooler.

19. The method of claim 12, further comprising:

in response to the revised lubricant temperature obtained according to the message related to APU is greater than AVG−

nδ

continuously and exceeding the predetermined number Z, issuing the warning of sensor.

20. The method of claim 1, further comprising:

estimating the time when the lubricant sensor encounter a malfunction.

21. A device for monitoring the performance of the lubricant cooler in aircraft auxiliary power unit APU, comprising:

message acquiring and analyzing unit, which acquires the APU messages within a time period, and obtains the operation parameters of the APU lubricant cooler, the operation parameters includes;

the time since installation TSR of APU, the lubricant temperature OTA and load compressor inlet temperature LCIT;

temperature revised unit, which obtains the revised temperature of lubricant OT;

revised temperature of lubricant OT=lubricant temperature OTA−

load compressor inlet temperature LCIT; and

performance monitoring unit, which determines that the performance of the APU lubricant cooler is in stable phase, decline phase, serious decline phase or malfunction phase according to the change trend of the revised lubricant cooler OT against the time since installation (TSR) of APU.

22. A device for monitoring the performance of the lubricant cooler in aircraft auxiliary power unit APU, comprising:

a processor; and

a memory linked with the processor, which stores the computer-readable codes;

the computer-readable codes run in the processor to execute the following steps;

acquiring the APU messages within a time period;

obtaining the operation parameters of the APU lubricant cooler, the operation parameters includes;

the time since installation TSR of APU, the lubricant temperature OTA and load compressor inlet temperature LCIT;

the revised temperature of lubricant OT is obtained by the following formula;

revised temperature of lubricant OT=lubricant temperature OTA−

load compressor inlet temperature LCIT;

determining that the performance of the APU lubricant cooler is in stable phase, decline phase, serious decline phase or malfunction phase according to the change trend of the revised lubricant cooler OT against the time since installation (TSR) of APU.