Method for monitoring reducing chemical solution i.e. aqueous urea solution, in internal combustion engine of motor vehicle, involves determining absorption spectrum produced by sample illuminated by incident spectrum of given wavelengths
The method involves setting the temperature of a sample of chemical solution in a predetermined range of temperature, by measuring the temperature of the solution and heating the solution as long as the temperature of the solution is less than the predetermined range of temperature. An absorption spectrum produced by the sample illuminated by an incident spectrum of given wavelengths is determined. Presence of absorption peak of a predetermined chemical compound e.g. ammonia precursor or solvent such as water, is identified from the absorption spectrum. An independent claim is also included for a device for controlling a chemical solution, comprising a reservoir.
