Patent ID: 8303766

Claim:
A method for evaporating a predeterminable volume of a fluid, the method comprising the following steps: providing a urea and water solution as the fluid for providing ammonia as a reducing agent in exhaust gas of internal combustion engines; calculating the predeterminable volume of the fluid from a nitrogen oxide concentration present in the exhaust gas; dividing the predeterminable volume of the fluid into individual partial volumes of different size; a) successively adding at least one first partial volume of the predeterminable volume of the fluid into a feed line at a first volume adding rate, and successively adding at least one second partial volume of the predeterminable volume of the fluid, being different from the at least one first partial volume, into the feed line at a second volume adding rate; b) at least partially evaporating the partial volumes to form a vapor film between the at least one first partial volume and a wall of the feed line; c) guiding the partial volumes through the feed line to an evaporator surface; and d) applying the partial volumes to a region of the evaporator surface disposed at a position varying as a function of at least one of the following parameters: i) a mass of the corresponding partial volume, or ii) a volume adding rate of the corresponding partial volume.