The EC has been warned that it risks boosting greenhouse gas emissions from Europe's road transport fleet if it sets the NOx limit for Euro 6 engines at too low a level. The comments come from Thomas Schlick (above), the head of the VDA, the German motor manufacturers' association, who also warns that with oil becoming a rarer commodity the sector will not welcome increased fuel consumption that lower NOx limits will entail.
The lower the limit set for NOx, the greater the fuel consumption and CO2 greenhouse-gas penalty, says Schlick, though SCR after treatment would make the trade-off less severe. The EC has to choose between what it calls six alternative Euro 6 'scenarios', each comprising a different NOx and particulate limit pairing. The proposed NOx limits range from 2.0g/Kwh - unchanged from Euro 5 - to an ultra-severe 0.2g/kWh.
Schlick added that the final decision on Euro 6 requirements was also likely to be influenced by calls for certification procedures to be 
globally harmonised, through the establishment of world-harmonised transient and steady-state test cycles (WHTC and WHSC). That implied a close alignment between Euro 6 and the standards being set in the US by the Environmental Protection Agency for implemen-tation in 2010.