| abstract |
In a vehicle that is equipped with a selective catalytic reduction (SCR) device, the ammonia consumption amount is accurately predicted in the SCR catalytic convertor based on the ammonia amount consumed by NOx, and the absorbed ammonia amount is controlled to improve the purification performance of the NOx and responsiveness to a rapid variation of driving conditions such that the purification efficiency is enhanced. A method for controlling the urea injection amount of a vehicle may include calculating an entire consumption amount of ammonia that is necessary in an SCR catalytic convertor by applying an ammonia amount consumed by the NOx exhaust amount, an absorbed ammonia amount, an ammonia reaction ratio, an absorbed HC amount, and an deterioration, calculating a necessary urea amount by calculating a necessary ammonia amount corresponding to the calculated entire ammonia consumption amount, and injecting the necessary urea amount when the temperature of the SCR catalytic convertor is in a predetermined range. |