Comparison of fast and slow gas analysers on a Euro 6 vehicle

We recently used our own in-house powertrain testing facilities to compare our fast emissions analysers (100 Hz) with conventional bench and FTIR analyzers.  See the video below for Euro 6 GDI cold start engine-out and tailpipe measurements of NO, NO₂  and HC.  Of particular interest is the (perhaps never seen before...?) spike of NO₂ evident in the tailpipe on the first combustion events following decel fuel shut-off (DFSO).  Euro 7 presents challenges for NO₂ and therefore this might be of wider interest with the possibilities of calibrating out these emissions through fuelling, internal EGR and throttle control.