Method and system for detecting misfire of internal combustion engine

PURPOSE: To provide an improved method and system that detects which of continuous or intermittent engine misfire at real time low-costly, efficiently and reliably during stable operation, acceleration or deceleration of an engine. CONSTITUTION: The method has a step of obtaining the electric signals including the data representing angular velocity of a crankshaft, a step of obtaining the data to be filtered for minimizing the effects of random error and disturbance of the electric signals, and a step of calculating M-dimensional torque non-uniformity vector that is derived from the filtered data. Furthermore, a step of calculating at least one reference torque value based on the torque non-uniformity vector, a step of estimating indication torque given by at least one cylinder based on the angular velocity of crankshaft during a given cycle of the engine, and a step of obtaining the misfire signal by comparing at least one reference value with the indication torque, are provided.