Diesel Particulate Filters (DPF) made of cordierite are generally used for diesel engine aftertreatment systems in both on-road and commercial off-highway vehicles to meet today’s worldwide emission regulations. PM/PN and NOx emission regulations will become more stringent worldwide, as represented by CARB2027 and Euro7. Technologies that can meet these strict regulations are required. As a result, aftertreatment systems have become more complex with limited space.
Recently, off-highway OEMs have been interested in downsizing the aftertreatment system using concepts such as DOConFilter in an effort to reduce the size of the exhaust system. DOConFilter can effectively replace DOC + CSF or DOC + bare DPF systems with a single zone coated particulate filter.
DOConFilter systems have an increased amount of coating compared to CSF as higher-filtration filters will become the norm. An undesirable increase in pressure drop is expected by adopting this new technology. In addition, soot regeneration efficiency will be another challenge in the application of this new technology. Therefore, optimization of the DOConFilter material and filter cell structure is needed in order to achieve aftertreatment system downsizing, while minimizing any system drawbacks.
NGK has developed several Cd-DPF materials which will be optimal for future regulations. NGK has also focused on the integration of high cell density and thin wall cell structures for effective soot regeneration efficiency.
In this paper, performance of both large and conventional cell structures has been compared under the DOConFilter catalyst. The DOConFilter catalyst included both conventional and newer materials for future tighter regulations. Pressure drop performance with and without soot have been evaluated before and after coating.
In addition, soot regeneration efficiency performance has also been evaluated to assess concerns on DOConFilter. With these results, we will show how this innovation will bring benefits to future aftertreatment systems.