Abstract: A misfire determination device of an internal combustion engine, includes an angular velocity obtaining section which obtains two crank angular velocities corresponding to two crank angular positions, respectively, which are set between a range which is around a first compression top dead center and a range which is around a second compression top dead center, in which the first compression top dead center is a compression top dead center of a determination target cylinder, and the second compression top dead center is the compression top dead center of a next ignition cylinder in which ignition is performed next to the ignition performed in the determination target cylinder; and a misfire determination section which determines whether or not misfire has occurred in the determination target cylinder based on a result of comparing a deviation between the two crank angular velocities to a predetermined misfire determination threshold.

Abstract: A misfire determination device of an engine in which explosion occurs at unequal intervals, the engine including a plurality of cylinders and a crankshaft which is angularly displaced at a different angle between expansion strokes, is configured to calculate generated torque correlation amount correlated with generated torque, based on an angular position signal of the crankshaft, and perform misfire determination, based on an average value of the generated torque correlation amount in an interval less than one cycle of the engine, at an angular position of the crankshaft which is different from an angular position of the crankshaft at an ignition timing.

Abstract: A misfire determination device of an internal combustion engine, includes an angular velocity obtaining section which obtains two crank angular velocities corresponding to two crank angular positions, respectively, which are set between a range which is around a first compression top dead center and a range which is around a second compression top dead center, in which the first compression top dead center is a compression top dead center of a determination target cylinder, and the second compression top dead center is the compression top dead center of a next ignition cylinder in which ignition is performed next to the ignition performed in the determination target cylinder; and a misfire determination section which determines whether or not misfire has occurred in the determination target cylinder based on a result of comparing a deviation between the two crank angular velocities to a predetermined misfire determination threshold.

Abstract: A misfire determination device of an engine in which explosion occurs at unequal intervals, the engine including a plurality of cylinders and a crankshaft which is angularly displaced at a different angle between expansion strokes, is configured to calculate generated torque correlation amount correlated with generated torque, based on an angular position signal of the crankshaft, and perform misfire determination, based on an average value of the generated torque correlation amount in an interval less than one cycle of the engine, at an angular position of the crankshaft which is different from an angular position of the crankshaft at an ignition timing.