RDE: TRANSIENT ON-BOARD NO_X EMISSIONS FROM A EURO 6 DIESEL WITH SCR

摘要

The European Commission is concerned over the lack of improvement in urban air quality. This concern centres on discrepancies between laboratory-based test cycles e.g. NEDC, and real world driving conditions. This led, in September 2017, to the introduction of RDE legislation mandating use of PEMS. Legislation defines a conformity factor of 2.1, to allow for the variability inherent in RDE. Initial testing has already shown that many vehicle calibrations are insufficient to achieve this limit. The key problem areas lie within transient operation of the engine; the cold-start, deceleration fuel cut-offs and hard accelerations. These transients are even more prevalent in real world driving scenarios and subject to increased variability due to driving style, ambient conditions and traffic. This increases the importance of calibrating for good emissions performance across the entire speed/load map.