INTRODUCTION
To meet new tailpipe emission regulations in 2015 in Europe a large proportion of diesel cars are expected to be equipped with an exhaust gas aftertreatment system called Selective Catalytic Reduction (SCR) to reduce emissions of nitrogen oxides (NOx).
In order to reduce NOx to the harmless components nitrogen and water, a SCR system needs ammonia. Because pure ammonia has - so far - been considered unsafe to carry onboard a vehicle the automotive industry has adopted a water-based ammonia solution called urea - trade name AdBlue in Europe and Diesel Exhaust Fluid (DEF) in USA.
A Danish clean-tech company called Amminex A/S has introduced an alternative technology that stores ammonia in a solid form, called AdAmmine™. Just as a sponge can absorb water, AdAmmine™ binds ammonia, and it can hold large quantities. A solid brick of AdAmmine™ can store the same quantity of ammonia as a cylinder with compressed, liquid ammonia of the same size.
"Out of the Blue" is a consortium of major automotive manufacturers interested in solid ammonia systems, who have joined forces to study the technology and share experiences.
Solid ammonia system
Amminex has developed a solid Ammonia Storage and Delivery System, ASDS that allows for compact and safe on-board storage of ammonia in replaceable cartridges. Ammonia is released on demand from the cartridge by controlled heating - either electrical heating or engine coolant waste heat. Both types of heating mechanisms are based on technologies that are mechanically simple. A small rechargeable start-up unit ensures ammonia dosing shortly after cold start - even under freezing conditions.
An Ammonia Flow Manifold (AFM) ensures dynamic and accurate dosing according to OEM demand signal and once ammonia is dosed to the exhaust line upstream of the catalyst, the ammonia gas allows for optimal reduction of NOx.
In summary, the existing challenges of liquid-based systems are eliminated:
Direct ammonia dosing to the exhaust line
Works at low exhaust temperatures
Easy to control dosing
Low risk of deposits in the exhaust line
High NOx conversion during urban driving
Mechanically simple
User friendly: No refilling by consumer needed
Very long shelf life of the ammonia storage substance
Lower installed weight and volume compared to an equivalent liquid system
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