Patent ID: 7047727
Filing Date: 2006-05-23
Classification: F02D,Y02T

Abstract:
1. A method for rapidly warming a catalyst for purifying exhaust gas from an internal combustion engine, the method comprising: performing irregular injection dither control after start-up of the internal combustion engine to rapidly warm said catalyst, the irregular injection dither control irregularly switching injection modes between a lean injection mode in which fuel is injected such that air-fuel ratio is leaner than a stoichiometric ratio and a rich injection mode in which fuel is injected such that a fuel-ratio is richer than a stoichiometric ratio, wherein the irregular injection dither control irregularly switches the injection modes in at least one cylinder so that there are more lean injections than rich injections in said at least one cylinder during the irregular injection dither control, and the irregular dither control irregularly switches injection modes in such a pattern that the rich injections do not occur consecutively for the same cylinder, in any of the cylinders, during the irregular injection dither control.