Next Generation Cordierite Thin Wall DPF for Improved Pressure Drop and Lifetime Pressure Drop Solution

摘要

Diesel particulate filters (DPF) have become a standard aftertreatment component for a majority of current on-road/non-road diesel engines used in the US and Europe. The upcoming Stage V emissions regulations in Europe will make DPFs a standard component for emissions reductions for non-road engines. The tightening in NOx emissions standard has resulted in the use of selective catalytic reduction (SCR) technology for NOx reduction and as a result the general trend in engine technology as of today is towards a higher engine-out NOx/PM ratio enabling passive regeneration of the DPF. The novel filter concept discussed in this paper is optimized for low pressure drop, high filtration efficiency, and low thermal mass for optimized regeneration and fast heat-up, therefore reducing CO_2 implications for the DPF operation. In addition, compact filter designs can be achieved by using the proprietary Asymmetric Cell Technology (ACT) providing a larger inlet channel volume and therefore a higher ash storage capacity in the same space envelope without compromising the filter bulk heat capacity and mechanical integrity. In this paper we will discuss two cell technologies of this novel filter concept: (i) standard cell technology for the highest reduction in pressure drop, improved filtration with increased ash storage capacity compared to conventional DPFs, and (ii) ACT design for a life time pressure drop solution. The benefit from ACT design may be utilized in different ways depending on the application requirements, like lower lifetime pressure drop or longer service interval for the same filter size or a smaller filter volume with the same service interval compared to conventional DPF systems. The filter technologies are based on a thin-wall design with optimized material and microstructure, resulting in very linear pressure drop response with soot loading in both bare and catalyzed state.