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:
Feb. 05, 1991
Filed:
Oct. 11, 1989
W Thomas Irick, New Haven, IN (US);
Michael R Singer, Fort Wayne, IN (US);
Navistar International Transportation Corp., Chicago, IL (US);
Abstract
The electrical system of a vehicle includes a primary voltage source for starting and operating the engine of the vehicle and an auxiliary voltage source for operating the electrical accessories of the vehicle, particularly when the engine is not operating, and a voltage differential monitor circuit for warning the vehicle operator of the existence of a low voltage condition of the auxiliary battery, such as resulting from an auxiliary battery charging system failure which could result in the inability of an electrical accessory to operate even when the engine is operating. The voltage differential between the primary and auxiliary sources is measured by coupling same to a voltage comparison device, namely a pair of voltage dividing resistor pairs providing inputs to an operational amplifier in which an output is turned on when the voltage differential is above a predetermined value determined by the voltage division ratio of the resistors causing the amplifier to direct a signal to a switching device, a field effect transistor, which in turn completes a circuit to a lamp causing same to become illuminated, the illuminated lamp warning the operator of the system failure.