Patent ID: 10309872

Abstract:
A misfire determination apparatus includes a rotation variation amount acquisition unit that obtains a rotation variation amount (ΔNE), which is a difference between a first angular velocity variation amount (Δω1) obtained during an expansion stroke of an arbitrary cylinder of a multi-cylinder internal combustion engine and a second angular velocity variation amount (Δω2) having been obtained in relation to a cylinder that has reached the expansion stroke N (where N is a positive integer) revolutions of a crankshaft before the arbitrary cylinder reaches the expansion stroke, and a misfire determination unit that, when the obtained rotation variation amount (ΔNE) exceeds a predetermined threshold (ΔNEth), determines that a misfire has not occurred in the internal combustion engine when a predetermined condition is established, and determines that a misfire has occurred in the internal combustion engine when the predetermined condition is not established.