Driving on-the-road has more frequent and prompt acceleration/decelerations than in the type-approval light-duty test conditions (NEDC), with Real Driving Emissions (RDE) of CO2 and NOX known to be considerably higher. Despite permissible limits of NOX emissions at type approval reducing significantly, in-service emissions from diesel vehicles have, in reality, not reduced at all through the Euro 1–5 / I–V emission standards. TfL commissioned a programme of laboratory testing to better understand the in- service emission performance of Euro 6/VI vehicles over the TfL London Drive Cycle (LDC). This cycle was constructed from instrumented car data making repeated circuits of a set route at different times of day. Twelve Euro 6 passenger cars were tested over the entire 140 kms of the LDC from a warm-start. Three HGVs were tested over the suburban sub-cycle (40kms) in laden and un-laden condition. NOX emissions from the petrol cars were at a low level and below, or at, their type approval limit of 0.06 g.km-1. Only one SCR equipped diesel car achieved NOX emissions close to their 0.08 g.km-1 type approval limit. NOX emissions from diesel cars with only LNT NOX controls were between 3 and 13 times higher than their type approval limit (conformity factors). A diesel supermini was emitting NOX at the same level as the fully laden 40T artic HGV tested.
Keywords: real driving emissions(RDE), CO2, NOX, Euro 6/VI, laboratory testing.