Preventing underestimation of soot load on diesel particulate filters by detecting soot retention

摘要

One method of determining a need to perform regeneration of a diesel particulate filter in the exhaust gas of a diesel engine tells a soot load of a diesel particulate filter with a pressure change based estimate of a soot load based on a pressure change across the diesel particulate filter at a first time and a second time ahead. A retention capacity of the diesel particulate filter is calculated based on the pressure change across the diesel particulate filter the first time and the second time. The method changes from the estimation of the soot load based on a pressure change to a model-based soot accumulation estimate for the soot load of the diesel particulate matter filter as soon as the retention capacity falls below a predetermined threshold value. The regeneration of the diesel particulate matter filter is requested after the estimated amount of soot based on the soot accumulation model has reached a preset amount.