Low refrigerant charge detection system for a heat pump

• US 5,186,014 A
• Filed: 07/13/1992
• Issued: 02/16/1993
• Est. Priority Date: 07/13/1992
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Runk, Robert M.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/912,374
• Time in Patent Office: 218 Days
• Field of Search: 62/129, 62/125, 62/126, 62/127, 62/158, 62/160
• US Class Current: 62/129
• CPC Class Codes: F25B 2500/222 Detecting refrigerant leaks
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence

Abstract

A low refrigerant charge detector is operatively connected in either the suction or discharge line of a compressor of a heat pump system, wherein the compressor is in turn connected to a reversing valve. The detector includes a pressure sensor connected in one line and transmits pressure readings to a computer. During reversal of the flow of liquid in the system by the reversing value, the time at which the pressure exceeds or drops below a predetermined value is measured. The comparison depends on if the sensor is connected in the suction line or discharge line. If the time exceeds a minimum time, a low charge of refrigerant is indicated.

Claims

1. A method of detecting low refrigerant charge in a heat pump system of the type having a compressor operatively connected to a reversing valve, the method including the steps of:

sensing the pressure of the refrigerant at a fluid line of the compressor,

detecting a first time at which the sensed pressure crosses a first predetermined pressure value in response to reversal of the reversing value and reversal of the fluid flow direction,

detecting a second time at which the sensed pressure crosses a second predetermined pressure value, and

indicating a low refrigerant charge in the heat pump system when the time difference between the first and second times crosses a predetermined value.

2. A method of detecting low refrigerant charge in a heat pump system of the type having a compressor operatively connected to a reversing valve, the method including the steps of:

sensing the pressure of the refrigerant flowing in one fluid line of the compressor connected to the reversing value,

detecting the time period that the sensed pressure crosses a predetermined switching pressure in response to reversal of the fluid flow direction by reversing the reversing valve,

indicating a low refrigerant charge in the heat pump system when the time period crosses a predetermined value.

3. A detection apparatus for detecting low refrigerant charge in a heat pump system of the type having a compressor operatively connected by fluid lines to a reversing value and including an evaporator and expansion device and condenser, said apparatus comprising;

pressure sensing means operatively connected to a fluid line of the compressor for sensing the pressure of refrigerant flowing in the fluid line to produce a pressure signal indicative thereof,

computer means for receiving said pressure signal and for determining the time period that the sensed pressure crosses a predetermined switching pressure in response to reversal of the fluid flow direction by reversing the reversing value and for producing a warning signal; and

indicating means for receiving said warning signal and for producing an indication of low refrigerant charge.