Engine speed calculating apparatus

摘要

An engine speed calculating apparatus capable of calculating an engine speed without being affected by pulsating revolutions in a low engine speed range. A time required for a crankshaft of an engine to revolve through a predetermined angle is measured upon each completion of revolution through the predetermined angle, and an engine speed is calculated on the basis of measured result data of the time required for revolution through the predetermined angle. When the preceding calculated engine speed is determined to be lower than a predetermined engine speed, an engine speed is calculated on the basis of a time required for the crankshaft to revolve through an angle larger than the predetermined angle.