An emission control system for an engine

摘要

A system is disclosed for regenerating a lean NOx trap 104 arranged to receive exhaust gases from a lean burn engine 101 in which during regeneration of the lean NOx trap 104 the flow of exhaust gases through the lean NOx trap 104 is prevented, the exhaust gasses are diverted past the lean NOx trap 104 through a bypass passage 190 and the outlet from the lean NOx trap 104 is connected to an air intake 112 of the engine 101 so as to recycle the products of regeneration through the engine 101. In a preferred embodiment two lean NOx traps 4A, 4B are arranged in parallel thereby permitting one of the lean NOx traps 4A, 4B to be regenerated while the other of the two lean NOx traps 4B, 4A continues to store NOx.