Method for controlling an oxygen concentration

摘要

A method is disclosed for controlling a concentration of oxygen that is measured by an oxygen sensor of an after-treatment system of an internal combustion engine when a regeneration of an after-treatment device is required. The method may be a computer-implement method. An oxygen sensor target value is lowered in a stepped phase as a function of an exhaust gas flow speed as the exhaust gas passes through the after-treatment system. The oxygen sensor target value is lowered evenly as a function of the exhaust gas flow speed and by a filter phase when a measured air/fuel ratio value is less than or equal to an AFR threshold value and until the oxygen sensor target value is equal to an oxygen sensor final target value. The oxygen concentration is controlled by applying the oxygen sensor target value.

主权项

1. A method for controlling a concentration of oxygen which is measured by an oxygen sensor of an after-treatment system of an internal combustion engine when a regeneration of an after-treatment device is required, the method comprising:
lowering an oxygen sensor target value (λtgt) in a stepped phase as a function of an exhaust gas flow speed as the exhaust gas passes through the after-treatment system; lowering the oxygen sensor target value (λtgt) evenly as a function of the exhaust gas flow speed and by a filter phase when a measured air/fuel ratio value (λ) is less than or equal to an AFR threshold value (λthr) and until the oxygen sensor target value (λtgt) is equal to an oxygen sensor final target value (Final λtgt); and controlling the oxygen concentration by applying the oxygen sensor target value (λtgt).