Method for controlling an internal combustion engine

摘要

The method involves adjusting a first air/fuel mass ratio for differentiating fuel injection to each purge while a second air/fuel mass ratio is constant such that purging of nitrogen oxide traps (38, 40) converges in few iterations to obtain a complete and simultaneous purging. The first air/fuel mass ratio is decreased in terms of a geometric sequence as a constant, and the second air/fuel mass ratio is unchanged when one of the nitrogen oxide traps is still partly full during the purge while the other nitrogen oxide trap is already completely drained. Independent claims are also included for the following: (1) a control unit (2) an internal combustion engine.