SILENCER INCLUDING A PARTICLE FILTER, A VAPORISATION PIPE AND A SCR-CATALYST

摘要

The invention relates to a silencer (12) for a combustion engine, which silencer (12) comprises a casing (20) with a substantially circular cylindrical shell surface (22), a first end element (24) and a second end element (26), at least one inlet (28) for leading an exhaust flow into the casing (20) and at least one outlet (30) for leading the exhaust flow out from the casing (20). The silencer comprises also a selective catalytic reduction (SCR) purification system which comprises an SCR substrate (32), a vaporisation pipe (34) and an arrangement (36) for adding a reducing agent to the exhaust flow in order to reduce NOx contents of the exhaust flow. The silencer further comprises a cylindrical particle filter (40) situated between a first space (38) and a first duct (39) such that the exhaust gases are led in a substantially radial direction through the filter (40). The exhaust flow is also caused to pass through a second duct (44) on the outside of the vaporisation pipe (34) before the SCR substrate in order to warm the vaporisation pipe (34). The silencer is of compact configuration and is flow-optimised such that the formation of urea crystals may also be reduced.