Abstract
This paper discusses dynamic characteristics of a urea SCR (Selective Catalytic Reduction) system. The urea flow rate to improve NO<SUB>x</SUB> conversion efficiency is generally determined by parameters such as catalyst temperature and space velocity. The urea-SCR system was tested in the various engine operating conditions governing the raw NO<SUB>x</SUB> emission levels, space velocity, and SCR catalyst temperature. These experiments include cold transients to determine catalyst light off temperature and urea flow rate transients. Likewise, ammonia storage dynamics was also investigated.<BR> The cold transient results indicate the light off temperature of the catalysts used in these experiments was 200-220℃. The ammonia storage and urea flow rate transients all indicate very slow dynamics (on the order of seconds), which presents control challenges for mobile applications. The results presented in this paper should provide an excellent starting point in developing a functional in vehicle urea SCR system.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
