Method of enhancing ammonia generation in an exhaust system of an internal combustion engine

摘要

Disclosed is a method of enhancing ammonia generation in an exhaust system 270 of an internal combustion engine 110 of an automotive system 100. The exhaust system comprises at least one after-treatment device 280, the after-treatment device being a lean NOx trap 281. The method is applied during a lean NOx trap LNT regeneration condition and comprises determining a post main injection amount of fuel that can be used to produce excess ammonia during a rich engine operating phase used for purging the LNT. The excess ammonia can then be used be a selective catalytic reduction SCR system downstream of the LNT. The method makes use of a combination of open-loop and closed-loop modelling methods. An automotive system and control software are also disclosed.