Performance Assessment of an Advanced Diesel Particulate Filter for Euro 7 Heavy-Duty Vehicles

The Euro 7 standard for Heavy-Duty (HD) vehicles introduces stricter Solid Particle Number (SPN) emission limits by reducing In-Service Conformity (ISC) thresholds from 9.8 × 1011 #/kWh to 9.0 × 1011 #/kWh and lowering the minimum detectable particle size from 23 nm (SPN23) to 10 nm (SPN10). SPN emissions are excluded from active regeneration of Diesel Particulate Filters (DPFs), but passive regeneration during ISC testing remains a regulated condition for HD vehicles. These stricter regulations underscore the pressing need for advanced DPF technologies to ensure compliance under real-world operating conditions. In this study, a Euro VI Step E HD vehicle was evaluated on an HD chassis dynamometer using a predefined real-world ISC testing route to assess SPN emissions during passive regeneration of soot-loaded DPFs. Two SPN instruments, one downstream of the DPF and one downstream of the subsequent Selective Catalytic Reduction (SCR), allowed for a parallel characterization of the DPF performance and the net SPN increase observed across the SCR system. The tests indicate that passive regeneration in Euro VI vehicles can lead to SPN10 emissions as high as 23 × 1011 #/kWh with current technology DPFs. However, the advanced DPF technology limited weighted DPF-out SPN10 emissions to 1.2 × 1011 #/kWh, below the net increase observed across the SCR system (2.3 × 1011 to 2.9 × 1011 #/kWh), even during passive regeneration events, presenting a feasible pathway for achieving compliance with future emission standards.