In order to meet the increasing vehicle exhaust emission standards, vehicle manufacturers and parts suppliers are continuous technological research and development, many technologies are emerging, in which SCR reduces particulate matter (PM) emissions through purifying within the machine, using the way of injecting urea solution into exhaust gas and to bring out the catalytic reduction reaction, and therefore to transfer the harmful NOx into harmless nitrogen and water.

 

China 5 new car of Dongfeng 2016 will be officially listed on December 17, it is learned, the new car will renew upgrading in these three aspects of technology, configuration, and services. In the process of upgrading the China 5 standards (National Phase V vehicle emissions, namely "China national standard 5"), this car's tail gas treatment unit is ultimately selected of the route SCR technology (Selective Catalytic Reduction). And moreover, the demonstration shows that, compared with China National 4 and other China National 5 cars; this technique has greatly promoted not only the discharge capacity, fuel economy, but also the fuel compatibility. Compared with the China National 4 cars, the car shows in a huge utility emissions, including nitrogen oxides reduced (NOx) by 28% and the particle concentration (PM) reduced by 82%, number of particulate matter particle (PN) reduced by 28%. Furthermore, since the SCR technology requires relatively low of the fuel quality, and also has the property of high sulfur tolerant, it has particular applicability in China which the supply of low-sulfur fuel in is far from adequate.

 

Denitration catalyst is the core of SCR technology, at present, vanadium pentoxide - tungsten trioxide (WO₃) / titanium dioxide denitration catalyst has been widely used in power plants and industrial boilers burning gas denitration. Vanadium pentoxide is easily poisoned by the alkali metal in fly ash, and shows of stability declined after being poisoned, thus to weaken the ability of redox catalyst; WO₃ improves the anti- poison ability of alkali of vanadium pentoxide, and thus enhance the DeNOx catalytic activity. In addition, WO₃ supplies the stable acidic sites on surface of catalyst, to improve the dispersibility of vanadium pentoxide, and finally improve the catalytic activity.