Method and system for control of at least one of a dosage device and an engine

A system arranged for controlling at least one of a dosage device and an engine, said engine producing an exhaust stream treated by an exhaust treatment system that injects at least one additive into said exhaust stream with said dosage device, wherein said additive evaporates in an evaporation chamber when being injected into said exhaust stream;

• the system comprising:
• means, arranged for determining at least one time dependent condition Ci of at least one position Pi at an internal wall of said evaporation chamber, said means being arranged for determining said at least one time dependent condition Ci at least based on one or more of at least one representation of an internal temperature Ti related to said at least one position Pi, respectively, said at least one representation of said internal temperature Ti being determined based on at least one temperature model for said evaporation chamber and one or more of at least one measurement and at least one prediction of an exhaust temperature Texh for said exhaust stream upstream said evaporation chamber in said exhaust treatment system;
• means, arranged for determining a risk for at least one critical condition Ci_critical related to said at least one position Pi based on said least one determined time dependent condition Ci such that said risk for at least one critical condition Ci_critical has a spatial resolution along said internal wall of said evaporation chamber;
• and
• means, arranged for controlling at least one of said dosage device and said engine based on said determined risk for at least one critical condition Ci_critical.