ADAPTIVE DEFROST CONTROLLER FOR A REFRIGERATION DEVICE

• US 20110088415A1
• Filed: 10/21/2009
• Published: 04/21/2011
• Est. Priority Date: 10/21/2009
• Status: Active Grant

• Current Assignee: Diehl AKO Stiftung & Company KG
• Original Assignee: Diehl AKO Stiftung & Company KG
• Inventors: Alvord, Robert, Lacey, Kevin, Kopec, Jim
• Granted Patent: US 9,032,751 B2
• Time in Patent Office: Days
• US Class Current: 62/80
• CPC Class Codes: F25B 2700/11 Sensor to detect if defrost is necessary
• CPC Class Codes: F25B 47/02 Defrosting cycles
• CPC Class Codes: F25D 21/006 with electronic control circuits
• CPC Class Codes: F25D 2600/02 Timing
• CPC Class Codes: F25D 2700/122 of freezer compartments
• CPC Class Codes: F25D 2700/123 more than one sensor measuring the inside temperature in a compartment
• CPC Class Codes: F25D 2700/14 Sensors measuring the temperature outside the refrigerator or freezer

Abstract

A system and method for controlling automatic defrost of a refrigerator device are provided. The system adaptively moves the defrost cycle to low usage times based on an evaluation of compressor usage in a daily cycle.

Claims

1. An adaptive defrost controller, comprising:

a processor configured to divide a cyclically recurring pre-defined time period into a plurality of bins, monitor compressor run times over the cyclically recurring pre-defined time period, log, over time, the detected compressor run times into the plurality of bins, analyze the data logged into the bins to detect bins recording low compressor usage, and schedule a defrost cycle based on the results of the analyzed data.

2. The adaptive defrost controller of claim 1, wherein the processor is a microcontroller.

3. The adaptive defrost controller of claim 1, wherein said processor monitors compressor run times by monitoring at least one of:

a relay or switch operation;

a detected voltage change;

a detected increased current draw; and

/or a temperature in at least one of a fresh food compartment and a freezer compartment.

4. The adaptive defrost controller of claim 1, wherein said processor is additionally configured to average the data logged into the bins prior to analyzing the data.

5. The adaptive defrost controller of claim 1, wherein the data is averaged using a low pass IIR filter or FIR filter.

6. The adaptive defrost controller of claim 1, wherein said defrost cycle is scheduled to occur during a targeted time period in a bin showing a past history of low compressor usage.

7. The adaptive defrost controller of claim 6, wherein said defrost cycle is started during the targeted time period instead of a requested compressor operation.

8. The adaptive defrost controller of claim 6, wherein the processor is additionally configured to accumulate a count of compressor run times during the cyclically recurring pre-defined time period, compare, in response to a defrost request, the accumulated count of compressor run times to a threshold, and if the threshold is not met, not to schedule a defrost cycle, but if the threshold has been met or exceeded, to schedule a defrost cycle during the next targeted time period.

22. The adaptive defrost controller of claim 6, wherein another control system of a refrigerator containing the adaptive defrost controller is signaled to start at the same time as said scheduled defrost cycle.

23. The adaptive defrost controller of claim 22, wherein the another control system is the control system for an ice maker.

24. The adaptive defrost controller of claim 1, wherein the analyzed data is additionally used by a diagnostic system of a refrigeration device.

25. The adaptive defrost controller of claim 3, wherein said processor monitors compressor run times by monitoring only a temperature of at least one of a fresh food compartment and a freezer compartment.

26. A refrigerator including the adaptive defrost controller of claim 25, wherein the adaptive defrost controller is located in the back of the refrigerator, near the evaporator, thereby allowing for more usable space in the fresh food compartment of the refrigerator

9. A method of performing a defrost cycle in a refrigeration device including an adaptive defrost controller, comprising the steps of:

dividing a cyclically recurring pre-defined time period into a plurality of bins;

monitoring compressor run times over the cyclically recurring pre-defined time period;

over time, logging the detected compressor run times into the plurality of bins;

analyzing the bins to detect bins recording low compressor usage;

scheduling a defrost cycle based on the results of the analyzing step; and

performing a defrost operation.

10. The method of claim 9, wherein at least the monitoring, logging and analyzing steps are performed by a microcontroller.

11. The method of claim 9, wherein the monitoring step monitors compressor run times by monitoring at least one of:

a relay or switch operation;

a detected voltage change;

a detected increased current draw; and

/or a temperature in at least one of a fresh food compartment and a freezer compartment.

12. The method of claim 9, further comprising the step of averaging the data logged into the bins prior to the analyzing step.

13. The method of claim 12, wherein the averaging step is performed using a low pass IIR or FIR filter.

14. The method of claim 9, wherein the defrost cycle is scheduled to occur during a targeted time period in a bin showing a past history of low compressor usage.

15. The method of claim 9, wherein the defrost operation is started during the targeted time period instead of a requested compressor operation.

16. The adaptive defrost controller of claim 14, further comprising the steps of:

accumulating a count of compressor run times during the cyclically recurring pre-defined time period;

comparing, in response to a defrost request, the accumulated count of compressor run times to a threshold; and

if the threshold is not met, not scheduling the defrost cycle at that time; and

if the threshold has been met or exceeded, scheduling the defrost cycle during the next targeted time period.

17. A computer program stored on a computer readable memory device, when executed by a processor, execution of the computer program causing the processor to perform the steps of:

monitoring compressor run times over a cyclically recurring pre-defined time period;

dividing the cyclically recurring pre-defined time period into a plurality of bins;

over time, logging the detected compressor run times into the plurality of bins;

analyzing the bins to detect bins recording low compressor usage; and

scheduling a defrost cycle based on the results of the analyzing step.

18. The computer program of claim 17, wherein the monitoring step monitors compressor run times by monitoring at least one of:

a relay or switch operation;

a detected voltage change;

a detected increased current draw; and

/or a temperature in at least one of a fresh food compartment and a freezer compartment.

19. The computer program of claim 17, wherein said computer program causes the processor to average the data logged into the bins prior to the analyzing step.

20. The computer program of claim 17, wherein the defrost cycle is scheduled to occur during a targeted time period in a bin showing a past history of low compressor usage.

21. The computer program of claim 17, which, when executed by a processor, causes the processor to perform the additional steps of:

accumulating a count of compressor run times during the cyclically recurring pre-defined time period;

comparing, in response to a defrost request, the accumulated count of compressor run times to a threshold; and

if the threshold is not met, not scheduling the defrost cycle at that time; and

if the threshold has been met or exceeded, scheduling the defrost cycle during the next targeted time period.