Exhaust line for heat engine of motor vehicle, has catalytic purification unit for purifying exhaust gas crossing bypass pipe, where unit has nitrogen oxide trap intercalated in downstream section between valve and gas releasing outlet

摘要

The line (10) has a main exhaust gas pipe (20) comprising a nitrogen oxide trap (26) intercalated between upstream and downstream sections (22, 24). A bypass pipe (28) is extended from a T-shaped intersection (30) with the upstream section until another T-shaped intersection (32) e.g. three way valve, with the downstream section through bypassing of the trap. A catalytic purification unit purifies the exhaust gas crossing the bypass pipe. The unit has another nitrogen oxide trap (38) intercalated in the downstream section between the valve and an exhaust gas releasing outlet (14).