Determination of ambient air temperature outside of an appliance

• US 5,533,349 A
• Filed: 12/16/1994
• Issued: 07/09/1996
• Est. Priority Date: 12/16/1994
• Status: Expired due to Fees

• Current Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Original Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Inventors: Nguyen, Yu T., Gromala, Joseph R.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US08/357,931
• Time in Patent Office: 571 Days
• Field of Search: 62/125, 62/126, 62/127, 62/129, 62/229, 62/209, 62/214, 62/215, 62/157, 62/231, 62/130, 236/94, 236/91 R, 236/91 D, 165/11.1, 165/28, 374/134, 374/141, 374/159
• US Class Current: 62/129
• CPC Class Codes: F02B 2075/027 four
• CPC Class Codes: F25B 2600/0251 with on-off operation
• CPC Class Codes: F25D 2400/04 Refrigerators with a horizontal mullion
• CPC Class Codes: F25D 2500/04 Calculation of parameters
• CPC Class Codes: F25D 2700/02 Sensors detecting door opening
• CPC Class Codes: F25D 2700/14 Sensors measuring the temperature outside the refrigerator or freezer
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A method for determining ambient air temperature outside of an appliance by making measurements inside the appliance. By measuring the time it takes a sensor to change inside the appliance from one temperature reading to another reading, the ambient temperature changes can be determined. Using this information, appliance performance can be optimized.

Claims

1. A method of establishing a program for determining the ambient temperature of air in an area surrounding an appliance, including a cold producing element, said method comprising the steps of:

establishing a first interior temperature set point for said appliance;

establishing a first exterior ambient temperature for said appliance;

establishing a second exterior ambient temperature for said appliance;

measuring first, the on and off times of said cold producing element for said first internal temperature set point and said first external ambient temperature condition;

measuring second, the on and off times of said cold producing element for said second internal temperature set point and said first external ambient temperature condition;

measuring third, the on and off times of said cold producing element for said first internal temperature set point and said second external ambient temperature condition;

measuring fourth, the on and off times of said cold producing element for said second internal temperature set point and said second external ambient temperature condition;

calculating from said first, second, third and fourth measurements, the average on times of said cold producing element for each of said measurements;

calculating the average off times of said cold producing element from said first, second, third and fourth measurements for each of said measurements;

establishing a graph and supporting equations based on the above average calculated on and off times to facilitate the determination of ambient temperatures in environments where the exterior temperature is not controlled.

2. A method of determining the ambient temperature of an area surrounding an appliance as claimed in claim 1 wherein:

the step of determining that the average on and off times of said cold producing element determines said average on and off times are not increasing;

providing an indication to said cold producing element that said ambient air temperature is not changing.

3. A method of determining the ambient temperature of an area surrounding an appliance as claimed in claim 1 wherein:

said cold producing element is a compressor.

4. A method of determining the ambient temperature of an area surrounding an appliance as claimed in claim 1 wherein:

said measuring step is performed by a microcontroller.

5. A method of determining the ambient temperature of an area surrounding an appliance as claimed in claim 1 wherein:

said calculating step is performed by a microcontroller.

6. A method of determining the ambient temperature of an area surrounding an appliance as claimed in claim 1 wherein:

said determining step is performed by a microcontroller.

7. A method of determining the ambient temperature of air in an area surrounding an appliance including a cold producing element said method comprising the steps of:

measuring the on times of said cold producing element;

measuring the off times of said cold producing element;

calculating the average on time of said cold producing element;

calculating the average off time of said cold producing element;

determining whether the average off time is decreasing;

determining whether the average on time is increasing;

determining an indication of a rising ambient temperature based on the presence of an increase in the on times of said cold producing element;

providing said indications of ambient temperature changes to said appliance to further control said cold producing element.

8. A method of determining the ambient temperature of air in an area surrounding an appliance as claimed in claim 7 wherein:

the step of determining the average on time of said cold producing element determines said on time is increasing provides an indication to said cold producing element that said ambient temperature is falling.

9. A method of determining the ambient temperature of an area surrounding an appliance as claimed in claim 7 wherein:

said cold producing element on time is increased in response to a determination of a higher ambient temperature.

10. A method of determining the ambient temperature of air in an area surrounding an appliance including a cold producing element said method comprising the steps of:

measuring the on times of said cold producing element;

measuring the off times of said cold producing element;

calculating the average on time of said cold producing element;

calculating the average off time of said cold producing element;

determining whether the average off time is increasing;

determining whether the average on time is decreasing;

determining an indication of a falling ambient temperature based on the presence of an decrease in the on times of said cold producing element;

providing said indications of ambient temperature changes to said appliance to further control said cold producing element.

11. A method of determining the ambient temperature of air in an area surrounding an appliance as claimed in claim 10 wherein:

the step of determining the average off time of said cold producing element determines said off time is increasing provides an indication to said cold producing element that said ambient temperature is falling.

12. A method of determining the ambient temperature of an area surrounding an appliance as claimed in claim 10 wherein:

said cold producing element off time is increased in response to a determination of a lower ambient temperature.