Patent ID: 7874203
Filing Date: 2011-01-25
Classification: G01M

Abstract:
1. A misfire detection apparatus for an internal combustion engine, which detects a misfire in an internal combustion engine that is provided in a vehicle, and that includes a plurality of cylinders, wherein the vehicle includes the internal combustion engine, a drive wheel, and a transmission mechanism that transmits torque output from the internal combustion engine to the drive wheel; the transmission mechanism includes a damper that reduces torsion of a component of the transmission mechanism, which is caused by the torque output from the internal combustion engine; and ignition is performed at a timing set based on a compression top dead center between a compression stroke and an expansion stroke, in each of the cylinders, the misfire detection apparatus comprising: a first detection portion that detects a rotational speed of an output shaft of the internal combustion engine; and a determination portion that determines whether a misfire occurs, based on an output of the first detection portion, wherein the determination portion determines that a misfire occurs in the internal combustion engine, if a first condition and a second condition are satisfied; the first condition is a condition that the rotational speed of the output shaft decreases by an amount equal to or larger than a first change amount during a time period from the compression top dead center in a first cylinder among the plurality of cylinders, to the compression top dead center in a second cylinder in which the ignition is performed subsequently to the ignition in the first cylinder; and the second condition is a condition that the rotational speed of the output shaft increases by an amount equal to or larger than a second change amount during a time period from the compression top dead center in the second cylinder, to the compression top dead center in a third cylinder in which the ignition is performed subsequently to the ignition in the second cylinder.