<div class="htmlview paragraph">A new method has been developed to close the ends of a wall flow filterused for removing particulate matter from diesel engine exhaust. In thismethod, the ends of the honeycomb structure are capped by deforming andclosing the ends of the channel walls between the extrusion and firingstages of production.</div> <div class="htmlview paragraph">The method increases the amount of filtration area per filter volume for agiven cell geometry conpared to the traditional plugging method, since theentire length of the honeycomb channels is used for filtration purposes.</div> <div class="htmlview paragraph">In addition, use of the capping method has a beneficial effect on thepressure loss characteristics of a filter with a given filtration area.These benefits are illustrated through experimental results.</div>