The invention proposes an exhaust-gas purification unit for purifying the
exhaust gas from an internal combustion engine which is preferably
operated in lean-burn mode, in particular a diesel engine used in motor
vehicles, in which a particulate filter and a SCR catalytic converter are
arranged in the exhaust pipe in succession in the direction of flow, and
having a reducing-agent supply, it being possible for ammonia to be added
to the exhaust gas from the internal combustion engine on the entry side
of the SCR catalytic converter by the reducing-agent supply. According to
the invention, the exhaust-gas purification unit includes a
hydrogen-generating unit for enriching the exhaust gas from the internal
combustion engine with the hydrogen which it generates. Use in motor
vehicles.