Exhaust-gas turbo charger`s operating state detecting method for motor vehicle, involves filtering specific frequency spectrum from pressure signal, applying evaluation logic, and evaluating frequency spectrum by utilizing Schmitt trigger

摘要

The method involves arranging a pressure sensor (6) at an entrance (4) of a compressor of an exhaust-gas turbo charger. The pressure sensor produces pressure signal and a bandpass filter filters a specific frequency spectrum from the pressure signal, where the bandpass filter has a single positive feedback. An evaluation logic is applied and the frequency spectrum is evaluated by utilizing a precision Schmitt trigger. An independent claim is also included for a device for performing a device for detecting an operating variable or an operating state of an exhaust-gas turbo charger.