The Horizon 2020 prize for the “Engine Retrofit for Clean Air” aims at reducing the pollution in cities by spurring the development of retrofit technology for diesel engines. A Euro 5 passenger car was retrofitted with an under-floor SCR (Selective Catalytic Reduction) for NO_x catalyst in combination with a solid ammonia based dosing system as the NO_x reductant. The vehicle was tested both on the road and on the chassis dynamometer under various test cycles and ambient temperatures. The NO_x emissions were reduced by 350–1100 mg/km (60–85%) in the laboratory depending on the test cycle and engine conditions (cold or hot start), except at type approval conditions. The reduction for cold start urban cycles was < 75 mg/km (< 15%). The on road and laboratory tests were inline. In some high speed conditions significant increase of ammonia (NH₃) and nitrous oxide (N₂O) were measured. No effect was seen on other pollutants (hydrocarbons, carbon monoxide and particles). The results of the present study show that retrofitting high emitting vehicles can significantly reduce vehicle NO_x emissions and ultimately pollution in cities.

地平线2020年“清洁空气发动机改造”奖旨在通过促进柴油发动机改造技术的发展来减少城市的污染。甲欧5乘用车用地板下SCR（选择性催化还原）改装为NO _X在催化剂组合与基于给药系统为NO固体氨_X还原剂。在各种测试周期和环境温度下，都在道路和底盘测功机上对车辆进行了测试。该NO _X在实验室中，根据测试周期和发动机条件（冷启动或热启动），排放量减少了350–1100 mg / km（60–85％），但类型批准条件除外。城市冷启动周期的减少量<75 mg / km（<15％）。公路和实验室测试是在线的。在某些高速条件下，测得氨（NH ₃）和一氧化二氮（N ₂ O）显着增加。没有发现对其他污染物（碳氢化合物，一氧化碳和颗粒物）的影响。本研究结果表明，改装高发光车辆可显著减少车辆NO的结果_X在城市排放并最终污染。