Retrofitting of diesel cars; Checking of manipulated trucks.

On behalf of the Clean Air platform, the possibilities of retrofitting diesel cars with exhaust gas treatment systems as well as the verification of manipulated trucks were analysed. The study concludes that due to the complexity of the exhaust gas aftertreatment, retrofitting would be most useful for heavy-duty vehicles that are travelling mainly in the urban area. Illegal manipulations concern mainly Euro V and VI trucks and are mostly carried out to circumvent the legally required monitoring of urea injection for exhaust gas purification. This can greatly increase NOx emissions. However, the detection of such manipulations is technically complex. A measurement program was able to detect both manipulations and defects.