Control of desulfurization of nitrogen oxides storage catalyst in IC engine exhaust system using sensor downstream from catalyst to determine its activity and desulfurization of catalyst if this falls below threshold value

摘要

Control of desulfurization of nitrogen oxides storage catalyst in IC engine exhaust system using sensor downstream from catalyst to determine its activity and desulfurization of catalyst if this falls below threshold value. Control of desulfurization of a nitrogen oxides storage catalyst in the exhaust system of an IC engine using an NO x sensor downstream from the catalyst produces a signal corresponding to the NO x concentration in the gas passing over it. The NO x activity of the catalyst is determined from this signal. When this falls below a threshold value the catalyst is given a desulfurization treatment with predetermined parameters. If, after desulfurization, irreversible damage to the catalyst is detected which exceeds a predetermined degree, a further desulfurization stage is carried out under more severe conditions. Operation of the engine is then modified to correspond to the new activity of the catalyst. An independent claim is included for equipment for carrying out the process.