Patent ID: 6199426
Filing Date: 2001-03-13
Classification: G01M

Abstract:
A method of detection of output fluctuation of a multi-cylinder engine having a crankshaft in which combustion is performed in a first cylinder and then combustion is performed in a second cylinder, comprising the steps of:setting a first crank angle range in a crank angle region in a middle portion of the expansion stroke a predetermined crank angle away from the first crank angle range;detecting a first angular velocity of the crankshaft in the second crank angle range;detecting a second angular velocity of the crankshaft in the second crank angle range;finding an amount of change between the first angular velocity at a time of a previous combustion and the first angular velocity at another time of a next combustion for the first cylinder;finding an amount of change between the first angular velocity at the time of a previous combustion and the first angular velocity at the another time of a next combustion for the second cylinder;finding an assumed second angular velocity at the time of the next combustion of the first cylinder when assuming that the output of the first cylinder will not fluctuate, on a basis of the amount of change of the first angular velocity for the first cylinder, the amount of change of the first angular velocity of the second cylinder, and the second angular velocity at the time of the previous combustion of the first cylinder; anddetecting the output fluctuation of the first cylinder based on the assumed second angular velocity and an actual second angular velocity at the another time of the next combustion of the first cylinder.