Rotational speed estimation device, multi-cylinder internal combustion engine, and control device for multi-cylinder internal combustion engine

摘要

A rotational speed estimating device estimating a rotational speed of a rotating body having a plurality of blades based on an output value of a detecting part detecting passage of a blade of the rotating body over a predetermined position inside a housing holding the rotating body, configured to calculate as a reference blade passage time an elapsed time from when any one blade among the plurality of blades passes the predetermined position once each time the any one blade passes the predetermined position a predetermined number of times and estimate the rotational speed of the rotating body based on the reference blade passage time and the number of times the any one blade passes the predetermined position during the reference blade passage time when the reference blade passage time is a threshold value or more.