COLD-START EMISSIONS AND EXCESS FUEL CONSUMPTION AT LOW AMBIENT TEMPERATURES: UPDATE ON THE IMPACT OF EU5 AND EU6 TECHNOLOGY ON PASSENGER CARS

摘要

Latest development of engines and emission control devices in passenger cars to bring them in compliance with the last amendments of European directives for exhaust emissions (EU5 and EU6) has apparently improved also their performance with regard to cold-start related emissions, even if the targeted test procedure to specifically measure and control these emissions was included in the type approval requirements of new types already in year 2002. The test results presented in this paper demonstrate that cold-start performance has been gradually improved, and emission rates measured at low ambient temperatures (-7°C) have declined. However, the negative effect of cold environment with regard to fuel consumption and CO_2 emissions has not much diminished. Furthermore, diesel-fuelled cars are not subject to this cold-start emissions test at all, yet according to the test results, they emit high levels of oxides of Nitrogen (NO_x), that may be part of the apparent air quality problem encountered in many urban areas of the European Union.