Ammonia Storage and Delivery Systems for Automotive NO{sub}x Aftertreatment

摘要

It is well-known that ammonia is the active molecule for the selective catalytic reduction of NO{sub}x in diesel exhaust. However, the use of liquid ammonia for on-board storage in a pressure vessel has been excluded due to safety issues. The industry has thus far chosen urea dissolved in distilled water (AdBlue) for storage in order to overcome the safety issues, but critical challenges must be overcome for efficient vehicle integration when indirect ammonia storage in the form of urea is applied. These challenges are related to the handling of the liquid in the tank as well as the conversion of urea to ammonia and CO{sub}2 inside the exhaust line.