Potentiality of filter technology in particle emission control of future Euro VII heavy duty gas engines

In view of the Heavy-Duty Natural Gas engines spread, prompted by the decarbonisa-tion issue and the upcoming restrictive Euro VII regulations on particulate emission, FPT Industrial, CNR-STEMS and NGK have cooperated in the investigation of specific technologies for its abatement. The next emission requirements in terms of both number and diameter of emitted par-ticles represents a new challenge for the compliance of gas engines, although histori-cally considered as particulate matter-free. Different approaches can be followed to reach the arduous targets, both in terms of engine enhancement, acting on particle formation mechanism itself, and on the After-treatment System (ATS) for the abatement of the exhaust engine out emissions. The use of a Particulate Filter in combination with the Three-Way Catalyst (TWC) re-presents a viable solution to achieve high conversion of gas-phase criteria pollutants and high filtration efficiency. Goal of the present research activity is to characterize engine emissions upstream and downstream the ATS of a NG engine in terms of particles number, mass and size dis-tribution over the World Harmonized Transient Cycle (WHTCs). A significant presence of particles is linked to specific phases of the cycle, correspon-ding to strong accelerations after long idle periods, particularly noticeable at cold cycle starts.