Comparison of real driving emissions and chassis dynamometer tests on emissions of two fuels in three Euro 6 diesel cars

Real driving emissions (RDE) from passenger cars has come under close scrutiny in recent times due to a perceived divergence between stated certification performance and measured on-road performance. This has been most pointed in the case of NOx emissions from diesel cars. To build understanding of the emissions performance of latest available diesel passenger cars, Concawe has conducted a study of the chassis dynamometer (CD) and RDE performance of three vehicles. As well as Diesel Particulate Filters, (DPFs) two of the vehicles featured high and low pressure Exhaust Gas Recirculation (EGR) and aqueous urea-dosed Selective Catalytic Reduction (SCR) after-treatment, whilst the third used high pressure EGR and was fitted with a Lean NOx Trap (LNT). For each vehicle, triplicate tests were conducted over RDE, WLTC, NEDC and US06 cycles. The data generated provides insights into the on-road emissions performance of latest diesel passenger cars and how this compares to regulated emissions limits and results from CD tests run under comparable conditions. The study also examines fuel effects over RDE cycles in these modern vehicles.