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:
Dec. 30, 1980
Filed:
Apr. 12, 1979
Rupin J Javeri, Elk Grove Village, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An ignition spark timing circuit with switchable hysteresis for an internal combustion engine is disclosed. A crankshaft sensor produces a periodic input sensor signal, having a predetermined period, which initiates the action of a programmable voltage slope generator that produces a predeterminedly varying signal. This varying signal serves as an input to a comparator which also receives a switching threshold input, and the comparator output is utilized to determine the time occurrence of spark ignitions. A switchable feedback path is provided between the output of the comparator and its switching threshold input such that hysteresis for the comparator threshold input is provided during critical portions (T.sub.C) of the time period of the crankshaft position sensor signal when the comparator is expected to produce output signal transitions that determine the occurrence of spark ignitions. At other portions (T.sub.N) of the time period of the crankshaft position sensor signal, the comparator output cannot affect the threshold input of the comparator.