The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 1995
Filed:
Apr. 11, 1994
John H Blair, Westland, MI (US);
Norman H Dolinski, Grosse Pointe Woods, MI (US);
Gerhard A Dage, Franklin, MI (US);
George E Peck, Dearborn, MI (US);
Manfred Koberstein, Warren, MI (US);
Robert W Matteson, Ann Arbor, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
An apparatus for detecting is disclosed for detecting a low level of refrigerant circulating through a motor vehicle refrigerant circuit. The apparatus comprises an electronic logic module, and a pressure transducer and a thermistor preferably located in the refrigerant circuit between the compressor and the evaporator. The pressure transducer generates a signal indicative of the refrigerant pressure, from which the module derives a saturation temperature of the refrigerant. The saturation temperature is compared with the measured temperature to determine if a superheat condition exists indicative of low refrigerant charge exists. When the refrigerant remains at a predetermined level of superheating, the compressor clutch is disengaged to interrupt circulation through the refrigerant circuit. In an alternative embodiment, a pair of thermistors are respectively situated proximate an inlet and an outlet of an evaporator, and the module interrupts circulation when the outlet thermistor indicates a temperature more than a predetermined amount greater than the inlet thermistor. In a third embodiment, a pressure switch in the refrigerant circuit generates a signal when a predetermined pressure is reached, and the module interrupts circulation if the temperature of the medium at the predetermined pressure corresponds to a superheat condition.