Exhaust-gas turbocharger`s number of revolutions determining method for use in internal-combustion engine, involves evaluating characteristics of signal for determining number of revolutions of turbocharger by Fast Fourier transform

摘要

The method involves arranging a solid borne sound sensor (30) in an exhaust-gas turbocharger (24). A signal is supplied by the solid borne sound sensor. Characteristics of the signal are evaluated for determining number of revolutions of the exhaust-gas turbocharger. The signal of the solid borne sound sensor is evaluated by a Fourier transform or a Fast Fourier transform for certain frequencies. The number of revolutions is determined by comparing an output of the Fast Fourier transform with preset reference values. Independent claims are also included for the following: (1) a computer program that is programmed for applying in a method for determining number or revolutions of an exhaust-gas turbocharger of an internal combustion engine (2) an electrical storage medium for control and/or regulating a device of an internal combustion engine (3) a control and/or a regulating device for an internal combustion engine.