System and method for diagnosing the operation of air conditioner systems

• US 4,967,567 A
• Filed: 04/01/1988
• Issued: 11/06/1990
• Est. Priority Date: 12/10/1987
• Status: Expired due to Fees

• Current Assignee: Sun Electric Corp (Snap-On Incorporated)
• Original Assignee: Murray, Inc. (Briggs & Stratton Corporation)
• Inventors: Proctor, Robert H., Eichenlaub, Dennis P.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/176,539
• Time in Patent Office: 949 Days
• Field of Search: 62/125, 62/126, 62/127, 62/128, 62/129, 62/130, 62/176.1, 62/176.6, 236/94, 165/11.1, 364/551, 364/557, 364/558
• US Class Current: 62/127
• CPC Class Codes: B60H 1/00585 Means for monitoring, testing or servicing the air-conditioning
• CPC Class Codes: F25B 2345/007 characterised by the weighing of refrigerant or oil
• CPC Class Codes: F25B 43/00 Arrangements for separating or purifying gases or liquids in analysers or rectifiers F25B33/00; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat F25B40/00 takes precedence
• CPC Class Codes: F25B 45/00 Arrangements for charging or discharging refrigerant
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence

Abstract

A microprocessor provides a diagnostic capability, and includes tables of acceptable values of parameters, such as air discharge temperature, suction pressure, etc., for different automobile makes and air conditioner types; provision is made for adjusting the acceptable ranges of such values due to one or more ambient factors, of which ambient relative humidity may be one. The microprocessor, after determining whether the air conditioning system has a cycling or a non-cyling clutch and providing a valid set of actual system values based on whether the clutch is cycling or non-cycling, compares actual values to acceptable value ranges of the air conditioner operating values, and displays possible causes of air conditioner malfunction on a video screen. Self-testing of both the microprocessor and associated electrical elements, and of mechanical elements such as conduits, valves and a scale is performed. the operator may command the microprocessor to display, in smaller print, a relatively large volume of detailed instrucitonal material dealing with specific checking procedures or repair. An air conditioner charging station withdraws refrigerant from an air conditioner, reclaims it by removing certain materials, and returns the reclaimed refrigerant to the same air conditioner from which it was withdrawn, and also provides new, make-up refrigerant to the air conditoner, in the amount necessary to make a full charge.

Claims

1. A method for determining the cause of a malfunction in an air conditioning system for providing cooled air having a variable speed compressor, a condenser and an evaporator, comprising:

establishing ranges of acceptable system values including at least one of system suction pressure, system discharge pressure and evaporator discharge air temperature;

(b) determining at least one of ambient humidity and temperature;

(c) adjusting the ranges of acceptable system values dependent on at least one of ambient humidity and temperature;

(d) acquiring actual system values including at least one of discharge pressure, suction pressure, and the temperature of evaporator discharge air;

(e) determining the relationship of at least one actual value to the adjusted range of the corresponding acceptable system value; and

(f) determining possible causes of system malfunction based on the determined relationship between said at least one actual system value and said adjusted range of the corresponding acceptable system value.

2. The method of claim 1, wherein the ranges of acceptable system values are established initially including ambient temperature as a factor.

3. The method of claim 2, wherein the adjustment of the ranges of acceptable system values is by adjusting the ambient temperature factor in accordance with sensed ambient humidity.

5. The method of claim 1, and further comprising establishing a range of acceptable values of ambient temperature, determining if the sensed ambient temperature is within the acceptable range therefor, and indicating if the sensed ambient temperature is not within the acceptable range therefor.

4. The method of claim and further comprising establishing ranges of acceptable system values for each of a plurality of different air conditioning systems, wherein said sensing of system values is of one of said plurality of air conditioning systems, and wherein the relationship determination is the determining of the relationship of at least one acquired system value to the adjusted range of the corresponding acceptable system value for the air conditioning system of which the values are sensed.

6. A method for determining the cause of a malfunction in an air conditioning system having a variable speed compressor with operating clutch, a condenser and an evaporator comprising:

(a) establishing ranges of acceptable system values including at least one of system suction pressure, system discharge pressure and evaporator discharge air temperature;

(b) determining at least one of ambient humidity and temperature;

(c) adjusting the ranges of acceptable system values dependent on at least one of ambient humidity and temperature;

(d) acquiring successive sets of actual system values including at least discharge pressure, suction pressure, and the temperature of evaporator discharge air;

(e) determining from the actual system values whether the system has a cycling or non-cycling clutch;

(f) providing a valid set of actual system values based on whether the system has a cycling or a non-cycling clutch;

(g) determining the relationship of at least one actual value of the valid set of system values to the adjusted range of the corresponding acceptable system value; and

(h) determining possible causes of system malfunction based on the determined relationship between the at least one actual system value and the at least one acceptable system value.

7. The method of claim 6, wherein the ranges of acceptable system values are established initially including ambient temperature as a factor.

8. The method of claim 7, wherein the adjustment of the ranges of acceptable system values is by adjusting the ambient temperature factor in accordance with sensed ambient humidity.

9. The method of claim 6, and further comprising establishing ranges of acceptable system values for each of a plurality of different air conditioning systems, wherein said sensing of system values is of one of said plurality of air conditioning systems, and wherein the relationship determination is the determining of the relationship of at least one acquired system value to the adjusted range of the corresponding acceptable system value for the air conditioning system of which the values are sensed.

10. The method of claim 6, and further comprising establishing a range of acceptable values of ambient temperature, determining if the sensed ambient temperature is within the acceptable range therefor, and indicating if the sensed ambient temperature is not within the acceptable range therefor.

11. Apparatus determining the cause of a malfunction in an air conditioning system for providing cooled air having a variable speed compressor, a condenser and an evaporator comprising:

(a) first storage means for storing ranges of acceptable system values including at least one of system suction pressure, system discharge pressure and evaporator discharge air temperature;

(b) means for determining at least one of ambient humidity and temperature;

(c) means for adjusting the ranges of acceptable system values dependent on at least one of ambient humidity and temperature;

(d) means for acquiring actual system values including at least one of discharge pressure, suction pressure and the temperature of evaporator discharge air;

(e) means for determining the relationship of at least one actual value to the adjusted range of the corresponding acceptable system value;

(f) means for determining possible causes of system malfunction based on the determined relationship between at least one actual system value and at least one acceptable system value; and

(g) means for displaying the possible causes of system malfunction.

12. Apparatus for determining the cause of a malfunction in an air conditioning system having a variable speed compressor with operating clutch, a condenser and an evaporator comprising:

(a) first storage means for storing ranges of acceptable system values including system suction pressure, system discharge pressure, and evaporator discharge air temperature;

(b) first measuring means for measuring at least one of ambient humidity and temperature;

(c) adjusting means for adjusting the ranges of acceptable system values dependent on at least one of ambient humidity and temperature;

(d) second measuring means for measuring a set of actual system values including discharge pressure, suction pressure, and evaporator discharge air temperature;

(e) triggering means for triggering said second measuring means to quickly measure said set of actual system values at regular intervals;

(f) second storage means for storing successive sets 1-n of said actual system values measured by said second measuring means;

(g) determining and providing means for determining whether the air conditioning system has a cycling clutch or a non-cycling clutch and providing a valid set of actual system values based on whether the clutch is cycling or non-cycling;

(h) relationship determining means for determining the relationship of at least one actual value of the valid set of actual system values to the adjusted range of the corresponding acceptable system value; and

(i) diagnosing means for determining possible causes of system malfunction based on the determined relationship between at least one actual system value and at least one acceptable system value; and

(j) means for displaying the possible causes of system malfunction.

13. The apparatus of claim 12, said determining and providing means comprising first digital means for determining whether said clutch is cycling or non-cycling, second digital means for providing a valid set of actual system values for a non-cycling clutch, and third digital means for providing a valid set of actual system values for a cycling clutch.

14. The apparatus of claim 13, said second storage means comprising a plurality of registers R[1]-R[n].

15. The apparatus of claims 14, said triggering means comprising a first timer,

said first digital means comprising first comparator means for comparing the absolute value of the difference between the discharge pressures stored in R[1] and R[x] to a preset first threshold, x being an integer greater than 1 and less than or equal to n, and a second timer for generating a signal if it detects output from said first comparator within a preset interval,

said second digital means comprising second comparator means for comparing the absolute value of the difference between the discharge pressure stored in R[1] and R[y] to a present second threshold, y being an integer greater than 1 and less than or equal to n, third comparator means for comparing the absolute value of the difference between the suction pressures stored in R[1] and R[5] to a preset third threshold, first AND gate means for receiving the output of said second timer and said first and second comparator means, and first gate means for receiving the output of said first AND gate means for providing the values in R[1] to said relationship determining means upon receipt of a signal from said first AND gate, and

said third digital means comprising fourth comparator means for comparing the absolute value of the difference between the discharge pressures stored in R[2] and R[3] to preset fourth and fifth thresholds, fifth comparator means for comparing the absolute value of the difference between the discharge pressures stored in R[1] and R[2] to the fourth and fifth present thresholds, second AND gate means for receiving the outputs of said fourth and fifth comparator means with respect to the fourth preset threshold, and third AND gate means for receiving the outputs of said fourth and fifth comparator means with respect to the preset fifth threshold, flip flop means for receiving the output from said second timer and said second AND gate means, fourth AND gate means for receiving the output from said second timer, said flip flop means, and said third AND gate means, and second gate means for receiving the output of said fourth AND gate means and providing the values in R[3] upon receipt of a signal from said fourth AND gate means to said relationship determining means.

16. A method for determining the cause of a malfunction in an air conditioning system having a variable speed compressor, a condenser and an evaporator, comprising:

(a) establishing ranges of acceptable system values including at least one of system suction pressure, system discharge pressure and evaporator discharge air temperature;

(b) determining at least one of ambient humidity and temperature;

(c) adjusting the ranges of acceptable system values dependent on at least one of ambient humidity and temperature;

(d) acquiring successive sets of actual system values including at least discharge pressure, suction pressure, and the temperature of evaporator discharge air;

(e) determining from the actual system values whether the system is cycling or non-cycling;

(f) providing a valid set of actual system values based on whether the system is cycling or non-cycling;

(g) determining the relationship of at least one actual value of the valid set of system values to the adjusted range of the corresponding acceptable system value; and

,

(h) determining possible causes of system malfunction based on the determined relationship between the at least one actual system value and at least one acceptable system value.

17. The method of claim 16 wherein the ranges of acceptable system values are established initially including ambient temperature as a factor.

18. The method of claim 17 wherein the adjustment of the ranges of acceptable system values is by adjusting the ambient temperature factor in accordance with sensed ambient humidity.

19. The method of claim 16 wherein said determining of system cycling step is performed by analyzing compressor discharge pressures.

20. The method of claim 16 wherein said determining of system cycling step is performed by analyzing compressor suction pressures.