Experimental Study of Impact of Ash and Soot on Tail Pipe Particle Number
PN requirements have been implemented as part of the Euro 5b and Euro 6 emission standards and off hwy Stage V standards. The PN compliance is established by relying on creating soot layer on the DPF which has very high PN filtration efficiency. Off highway Stage V cycles are significantly higher in temperature than their on highway counterparts, leading to difficulty in the DPF to create and maintain a soot cake. Hence for these applications the meeting Particle Number Requirement is challenging. To meet PN on off highway engines, we will have to rely on DPF. This presents a challenge, since to meet the high filtration efficiency requirements the DPF will have to reduce mean pore size, pore standard deviation, and increase wall thickness, increasing backpressure, which results in a fuel consumption penalty. The other option is to evaluate ASH layer as a filtration mechanism to help in meeting PN regulation. This paper discusses the ability of ash to improve PN filtration.