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.

Date of Patent:
Apr. 17, 2001

Filed:

May. 24, 1999
Applicant:
Inventors:

Takeshi Shimizu, Tokyo, JP;

Koichi Okamura, Tokyo, JP;

Mituru Koiwa, Tokyo, JP;

Yutaka Ohashi, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01L 3/26 ; G01L 5/13 ; G01M 1/500 ;
U.S. Cl.
CPC ...
G01L 3/26 ; G01L 5/13 ; G01M 1/500 ;
Abstract

A combustion state detecting device for an internal combustion engine is obtained which is capable of preventing noises from being superimposed on an ion current, and surely obtaining a desired peak value of the ion current. The combustion state detecting device for the internal combustion engine includes an ignition coil which develops an ignition high voltage, an ignition plug to which the ignition high voltage is applied through a high-voltage path connected to a plurality of output terminals of the ignition coil, bias means for charging a bias voltage necessary for detecting ions which are discharged and generated from the ignition plug, discharge current limiting means for discharging the bias voltage, ion current detecting means for detecting the discharge of the bias voltage as an ion current that flows through the ignition plug, and an ECU for detecting a combustion state in the ignition plug on the basis of a detection value of the ion current, wherein the discharge current limiting means is disposed between an ignition current path formed by discharging the ions from the ignition plug and the bias means.


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