Patent ID: 6568174
Filing Date: 2003-05-27
Classification: F01N,F02D,Y02A,Y02T

Abstract:
Method for reducing warm-up emissions in the exhaust system of a direct-injection internal-combustion engine, comprising:adjusting a lean air/fuel mixture for the engine-related combustion, carrying out a late injection into the exhaust gas during the exhaust cycle of the internal-combustion engine, so that the exhaust gas contains an essentially stoichiometric air/fuel mixture, and igniting the stoichiometric air/fuel mixture contained in the exhaust gas in the proximity of a catalyst device for heating the catalyst device, wherein the catalyst device has a first catalyst close to the engine and a second catalyst away from the engine, which are arranged behind one another, and wherein the ignition takes place between the two catalysts; and further wherein the first catalyst is an NOx storage catalyst and the second catalyst is one of an NOx storage catalyst and a 3-way catalyst.