Transient Gaseous and Particulate Emissions Measurements on a Diesel Passenger Car including a DPF Regeneration Event

The gaseous and particulate emissions from a diesel passenger car have been studied during cold start and Diesel Particulate Filter (DPF) regeneration events occurring during the New European Drive Cycle (NEDC).

During the initial phase of the cycle, Diesel Oxidation Catalyst (DOC) light-off was seen to be highly dynamic with catalyst efficiency changing dramatically with changes in catalyst temperature.

Accumulation mode particulate emissions were sampled directly from the exhaust after the DPF. From cold start with a clean (regenerated) DPF, accumulation mode particle emissions were seen to be very much higher than those from a loaded DPF. This accumulation mode slip lasted only approximately 200 seconds.

During regeneration of the DPF, the oxidation of trapped soot was associated with a large tailpipe emission of nucleation mode particles. Chemical analysis of particulate matter suggests that this nucleation mode may be due to sulphur compounds being driven off as the soot is oxidised.