A method for operating an emission control system in a vehicle exhaust system.

摘要

The method comprises determining an amount of reductant required (for example urea/ammonia) 310, and applying the reductant in a mist to treat the exhaust gasses in a vehicle emission control system. In an embodiment the mist is formed by applying an ultrasonic field to a reductant-containing liquid 320 in a reductant storage device to generate a mist of the reductant-containing liquid; and selectively introducing an amount of mist to the exhaust system 330 coupled to the emission control system based upon an engine operating condition. The mist may be introduced with a low pressure gas stream. The ultrasonic film may be applied without direct heating. The amount of mist injected may be based on the ammonia or urea content. The ultrasonic device may be a harshly resonant diaphragm. The ultra sonic device may further be partially submerged in the stored reductant containing liquid.