Rotational speed measurement meter for motor, has analyzer to determine rotational speed based on periodicity of specific characteristic signal related to sound wave, output by sound transducer

摘要

A sound transducer positioned in an exhaust gas path of an internal combustion engine, converts the sound waves into specific characteristic signal related to sound wave. An analyzer determines the rotational speed based on periodicity of characteristic signal. An independent claim is also included for motor rotational speed determination method.