Patent ID: 6196183
Filing Date: 2001-03-06
Classification: B01D,F01N,F02B,F02D,F02P,Y02T

Abstract:
A method for changing an operating mode of a direct-injection Otto cycle internal-combustion engine between a stratified charge operation with a later fuel injection during a compression cycle and intake air supplied in an unthrottled manner, lean fuel/air mixture being formed with fuel/air ratios .lambda.>1, and an operating mode with a homogeneous mixture formation provided for higher load ranges of the internal-combustion engine by fuel injection during the intake cycle, comprising the steps of:operating the internal-combustion engine, for periodic regeneration of an NO.sub.x storage catalyst for decontaminating exhaust gases of the internal-combustion engine flowing through at lean fuel/air ratios, with the homogeneous mixture formation and rich fuel/air ratios below the stoichiometric mixture ratio .lambda.=1;at a change-over time, shifting the injection end of the fuel injection into a power cycle provided for a demanded operating mode;during a homogeneous operating phase bounded by the change-over time, apportioning a fuel quantity to be injected per power cycle corresponding to an actual intake air flow by adjusting the respective injection time; and adjusting an ignition point time isochronously and proportionally with a change of injection time in a direction toward a later ignition.