Patent ID: 8153072

Claim:
A hydrolysis catalyst configured for use in an exhaust system of a combustion engine, and operable for catalytic conversion of a uric substance to ammonia for use in another downstream SCR catalyst, the hydrolysis catalyst comprising a container with an engine exhaust gas inlet and an exhaust gas outlet, an active catalyst element accommodated in the container a valve configured to inject the uric substance into an exhaust flow from the engine, upstream, in the exhaust flow from the engine, of the active catalyst element, the active catalyst element comprising a central portion and a peripheral portion around the central portion, and each portion being comprised of a respective plurality of ducts passing through the catalyst chamber between the inlet and the outlet; the ducts being lined with a catalyst material operable for catalytic conversion of a uric substance to ammonia; cross-sectional areas of the separate ducts in the peripheral portion are larger than cross-sectional areas of the separate ducts in the central portion.