Patent ID: 6411080
Filing Date: 2002-06-25
Classification: F02D,F02P,G01P

Abstract:
A signal processing method for a variable reluctance sensor that is responsive to movement of a toothed wheel that rotates with a drive wheel of a vehicle, the vehicle having an engine that is selectively coupled to the drive wheel, the signal processing method comprising the steps of:processing an output signal of said speed sensor by selecting portions of the signal having an amplitude greater than a predefined amplitude threshold and a frequency less than a predefined filter frequency; determining a speed of said vehicle based on the selected portions of said sensor output signal; detecting a first condition of potentially erroneous speed sensing characterized by substantially stationary vehicle operation with the engine decoupled from the drive wheel and an engine speed in excess of a calibrated threshold; and raising said predefined amplitude threshold to a maximum value and lowering said predefined filter frequency to a minimum value so long as said first condition of potentially erroneous speed sensing is detected.