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. 10, 1981
Filed:
May. 17, 1978
Koukiti Yamada, Kariya, JP;
Katsuyuki Miyake, Kariya, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
A system for detecting rotational frequency of engine which comprises a switching device including a switching transistor for switching on and off the flow of current to the ignition coil of an internal combustion engine and a current limiting circuit for limiting the flow of current to the switching transistor to a predetermined value, and a speed detecting circuit connected to the junction of the ignition coil and the switching transistor. The speed detecting circuit is designed so that it has a threshold value voltage which is higher than the collector voltage of the switching transistor produced on limitation of current flow and which varies in response to the power supply voltage, and a signal is generated when the voltage at the junction of the ignition coil and the switching transistor exceeds the threshold value voltage, thus generating an output signal in synchronism with the spark ignition timing irrespective of variation in the supply voltage and thereby accurately detecting the engine speed irrespective of variation in the supply voltage.