Patent ID: 6768308
Filing Date: 2004-07-27
Classification: F02D,F02P,G01M

Abstract:
A misfire detecting device for an internal combustion engine comprising:sensors for sensing an operating condition of said internal combustion engine, operating area detecting means for detecting a divided operating area, on the basis of the rotation information of said internal combustion engine, control parameter calculating means for calculating a control parameter of said internal combustion engine, on the basis of the operating condition sensed by said sensors, an igniter for igniting said internal combustion engine in accordance with the control parameter, an ion current detector for detecting an ion current produced by ignition of said internal combustion engine, a first misfire determination means for determining a misfire of said internal combustion engine on the basis of a temporal change of the rotation information of said internal combustion engine contained in the operating condition sensed by said sensors, a second misfire determination means for determining a misfire of said internal combustion engine on the basis of the ion current, and misfire determination selecting means for selectively employing said first or second misfire determination means in accordance with the operating area, wherein when said operating area detecting means detects the operating area that is less than or equal to a predetermined rotation number, said misfire determination selecting means determines the misfire in accordance with a logical product between a detection result of said first misfire detecting means and a detection result of said second misfire detecting means.