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. 20, 1992
Filed:
Dec. 17, 1991
Sanden Corporation, Gunma, JP;
Japan Electronic Control Systems Company, Ltd., Gunma, JP;
Abstract
An air conditioning system having a circuit for determining whether sufficient refrigerant is present in the system by detecting a phase state of the refrigerant. The circuit comprises a comparison circuit for comparing a detection signal of a state detecting sensor with a first reference value and a second reference value lower than the first reference value. An indication signal is output after the detection signal exceeds the first reference value until the detection signal is less than the second reference value. When the amount of refrigerant in the system is proper, even if the detection signal varies due to translucent lubricating oil in the refrigerant, the indication signal is continued to be output unless the detection signal drops below the second reference value. The amount of refrigerant in the refrigerant circuit can be accurately determined and maintained within a proper range. If the detection signal becomes less than the second reference value from, for example, leakage of refrigerant, the amount of refrigerant in the refrigerant circuit can also be accurately determined as insufficient.