Patent ID: 9561470
Date: 2017-02-07
CPC Classifications: B01D,F01N,Y02A,Y02T

Claim:
1. A method for the purification of diesel engine exhaust gases, comprising: a) passing an exhaust gas to be purified through a diesel oxidation catalyst for oxidation of residual gaseous hydrocarbons and carbon monoxide in order to form carbon dioxide and for an at least proportional oxidation of nitrogen monoxide contained in the exhaust gas in order to form nitrogen dioxide; b) adding a urea-water solution that has been preconditioned in a urea-water solution heat exchanger integrated into a crankcase of the engine is added to the exhaust gas resulting from step a) and ammonia is released from the added urea through thermolysis and hydrolysis, the preconditioned urea-water solution having been heated up to 80° C. to 90° C. [176° F. to 194° F.] in the engine; c) passing the exhaust gas resulting from step b) through an SCR catalytically activated particulate filter in order to reduce the particles contained in the exhaust gas as well as the nitrogen oxides contained in the exhaust gas; and d) passing the exhaust gas resulting from step c) through a selective ammonia slip catalyst in order to reduce the residual contents of ammonia.