A Study on the Performance Deterioration of SCR for Heavy-Duty Diesel Vehicles

In this study, a six litres displacement, commercial vehicle engine that meets the EURO-5 regulation was used to evaluate the durability and performance deterioration of the SCR system mounted on a heavy-duty diesel vehicle. ESC and ETC modes were used for emission test. Characteristics of emissions by SCR catalyst deterioration were investigated using mileage vehicles of 0 km, 120,000 km, and 360,000 km. EDS (Energy Dispersive X-Ray Spectroscopy) analysis on PM filters and CT scan to catalyst substrate were carried out in order to investigate the status of catalyst by each mileage. As a result, it was found that NO_X, slipped NH₃ as well as PM due to unreacted ammonia and urea increased as the mileage of the catalyst increased.