DIAGNOSIS OF THE CONDITION OF A PARTICLE FILTER

摘要

An on-board diagnostic for a particle filter of a vehicle exhaust system records repeating data about flow and pressure around the particle filter. Data is recorded in virtual data bins having successive thresholds or filters within a numerical scale. Each data point is typically recorded in several bins to permit a rapid calculation of averaged data for use in the diagnostic. Sensitivity of less frequently recorded data is preserved, whilst giving quickly delivery of a result from the diagnostic.

主权项

1. A method of determining the condition of a component by period diagnostic check, said diagnostic check indicating behavior corresponding to ‘normal’ and ‘fault’ by reference to one or more pre-determined values, the method comprising:
providing a numerical scale of possible values for each of one or more variable parameters of a component, said values have progressively increasing quality from one end of said scale to the other end; defining in each said scale a plurality of successive thresholds, and providing for each threshold a virtual data bin; continually measuring said one or more variable parameters at a pre-determined time interval to obtain successive values of said parameters; for each successive value, placing the value in every corresponding data bin having a threshold on the lower quality side of said value; continually summing the values in respective data bins; defining for every data bin a trigger limit corresponding to a maximum sum of values; upon reaching the trigger limit in any bin, calculating the average value in said bin; using said average value in said diagnostic check by reference to said pre-determined value, and clearing the bin in which the trigger limit was reached for re-accumulation of successive values.