METHODS FOR DETERMINING WHEN TO REGENERATE EXHAUST GAS PARTICULATE FILTERS

摘要

Methods for determining when to regenerate an exhaust gas particulate filter (10), for regenerating, and for calibrating a pressure drop across such filters are disclosed. An example method involves reducing a first amount of particulates (52) accumulated in the filter to a residual amount RADP. The method also includes measuring the residual amount RADP by exciting the microwave resonant cavity (126) in which the filter resides with microwave radiation (182) and then monitoring the microwave cavity response. The method also includes using the measured value of RADP to calibrate a pressure drop threshold &Dgr;PTH SO that it is representative of a limit (TDP) of particulate accumulation in the filter. The methods may also include regenerating the filter a number of times and each time re-setting the pressure drop threshold &Dgr;PTH based on measurements of RADP taken after each filter regeneration.