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:
Jul. 27, 1993
Filed:
Feb. 12, 1992
Toshio Ohsawa, Himeji, JP;
Toshio Iwata, Himeji, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A combustion detecting apparatus for an internal combustion engine capable of discriminatively detecting the state of combustion, normal combustion or abnormal combustion such as misfiring, from each other. By applying a voltage of positive polarity to a spark plug for each engine cylinder, an ion current of negative polarity, which is generated upon combustion of a mixture in the cylinder, is detected. Subsequently, the detected ion current signal of negative polarity is transformed to a signal of positive polarity which is then subjected to waveform shaping by using comparators to obtain an ion current detection output signal which is utilized in making decision as to occurrence of misfiring. By making use of the ion current of negative polarity, a high signal level is realized to detect the state of combustion with high reliability even in a high speed or under a heavy load of the engine. By providing a low pass filter which can pass only a shaped signal component having a duration longer than a predetermined time, noise components usually of a short duration can be eliminated to improve combustion detection.