Patent ID: 6873941
Filing Date: 2005-03-29
Classification: F02D,G01P

Abstract:
1. A speed filter for an internal combustion engine whose speed is detected in a form of tooth timing values of a shaft and where from the tooth timing values by means of a filter a filtered tooth timing value, corresponding to an actual speed value, is calculated, comprising: a calculation rule for the complete elimination of a torsional vibration or partial elimination of said torsional vibration of the i wherein, by means of the calculation rule (BV(i)) certain tooth timing values are selected from earlier tooth timing-values (U(k−(N/2)), U(k−(N/3))) and the filtered tooth timing value (y(k), k=1,2,3 . . . ) is calculated (y(k)=f(BV(i))) by adding a current tooth timing value (U(k)) and the selected earlier tooth timing values.