| 摘要 |
<p>A method of determining the condition of a particle filter in a vehicle exhaust system to diagnose a fault. The method comprises providing a numerical scale of possible values for each of one or more variable parameters of the filter, the values having increasing quality from one end of the scale to the other, defining in each scale a plurality of successive thresholds, and providing for each threshold a virtual data bin or digital filter. The one or more variable parameters are measured at time intervals to obtain successive values of the parameters, and each successive value is placed in every data bin, or through every data filter, having a threshold on the lower quality side of the value. The values in respective data bins are continually summed, and, upon reaching a trigger limit in any bin, the average value in that bin in calculated. The average value, or an output of the digital filter, is used in a diagnostic check of the filter, and the bin in which the trigger limit was reached is cleared. The variable parameters may be a pressure differential, a dynamic head and/or a volume flow rate.</p> |
