Ultra-Low NOx Emissions with a Close-Coupled Emission Control System on a Heavy-Duty Truck Application

摘要

Heavy-duty vehicles represent a significant portion of road transport and they need to operate in a clean and efficient manner. Their emission control systems need to be enhanced to sustain the high conversion efficiencies seen during motorway conditions inother operating conditions. The European Commission is developing legislative proposals for Euro 7 emissions regulations for light- and heavy-duty vehicles. The new Euro 7regulation will likely focus on ensuring the emissions from heavy-duty vehicles are minimized over extensive on-road operating conditions and specifically on operating conditions such as urban driving and cold-start operation. These challenges are increased by the need to ensure low secondary emissions like NH_3 and N_2O, as well as a low impact on CO_2 emissions. The paper outlines the low pollutant emissions achieved by a heavy-duty Diesel demonstrator vehicle. The vehicle is equipped with an innovative layout of state-of-the-art emission control technologies, combined with an advanced controlstrategy on an existing Euro VI long-haul truck. The new emissions control system integrates a close-coupled DOC, a catalyzed DPF, dual-SCR system -one in a close-coupled position-, with twin AdBlue dosing controlled withFEV developed software. Both SCR catalysts contain an ammonia slip catalyst. The innovative system layout allows ultra-low NOx emissions and well controlled secondary emissions in even the most challenging conditions with minimal impact on CO_2 emissions. Pollutant emissions were evaluated over a broad range of operating conditions, including different payloads to show the emissions reduction potential. This paper also includes results obtained from the on-road Portable Emissions Measurement System (PEMS) testing.