Patent ID: 6560558
Filing Date: 2003-05-06
Classification: F02D,G01P

Abstract:
An engine speed calculating apparatus for measuring a time required for a crankshaft of an engine to revolve through a predetermined angle upon each completion of a revolution through the predetermined angle and calculating an engine speed on the basis of measured result data of the time required for a revolution through the predetermined angle comprising:determining means for determining whether the preceding calculated engine speed is lower than a predetermined engine speed; and calculating means for performing engine speed calculation on the basis of a time required for said crankshaft to revolve through an angle larger than said predetermined angle when said preceding calculated engine speed is determined to be lower than said predetermined engine speed, wherein in a high speed range, each period of time required for a revolution through the predetermined angle is used directly to calculate the engine speed, and wherein in a low speed range, the sum of a plurality of consecutive periods, each representing a time required for a revolution through the predetermined angle, is used to calculate the engine speed.