High Performance DPF to Tackle Nanoparticulate Emissions

Diesel Particulate Filters (DPF) have been used extensively worldwide as a Particle Mass (PM) / Particle Number (PN) reduction technology for various diesel applications. Based on CARB’s latest Tier 5 regulation workshop, PM emission targets are expected to become a lot more stringent; from 0.02 g/kWh to 0.005 g/kWh (75% reduction compared to Tier 4 Final). Also, CO2 emission targets are expected to be introduced for Tier 5. In parallel, EU Stage VI emission regulation standards and implementation timing could be announced sometime in late 2024. It is expected that PN emission standards will be tightened such as extending measurement range of PN from 23 nm to 10 nm. With Tier 5 and EU Stage VI regulations approaching, several OEMs are considering implementing a common aftertreatment system that can meet emission targets for both regions. High filtration efficiency and low backpressure DPFs will be required to meet PM/PN and CO2 emission standards. NGK has developed several DPF materials with various cell structures within the past couple of years to meet future stringent regulations worldwide. In order to understand the severity of future regulation, engine testing was conducted to compare PM / PN filtration performance of several different filters. Both Cordierite and SiC materials were evaluated since different materials are being considered depending on soot regeneration strategies, and DPF properties ranging from medium to low mean pore size (MPS) were studied and compared with Tier 5 PM / Stage VI PN targets as a reference point. In this paper, the suitable DPF for future regulation based on these results will be shown.