Retrofitting of diesel cars; Checking 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 exhaust after-treatment, retrofitting would be the most appropriate for heavy-duty commercial vehicles, mainly in urban areas. Illegal manipulation concerns mainly Euro V and VI trucks and are mostly carried out to circumvent the statutory monitoring of urea injection for exhaust gas purification. This allows NOx emissions to rise sharply. However, the detection of such manipulations is technically complex. A measurement program was able to detect both manipulations and defects.