Control device for direct injection engine

Abstract

To reduce the amounts of HC, NOx and other emissions from a direct injection engine when a catalyst is still in its unheated state, and to promote catalyst quick light-off operation by increasing the temperature of exhaust gases, a control device comprises a temperature state identifier (,) for judging the temperature state of a catalyst (,) and a fuel injection controller (,) for controlling fuel injection from an injector (,). The fuel injection controller (,) controls the injector (,) based on judgment results of the temperature state identifier (,) in such a way that the injector (,) makes at least two-step split injection during a period from an intake stroke to an ignition point including a later injection cycle performed in a middle portion of a compression stroke or later and an earlier injection cycle performed prior to the later injection cycle at least in a low-load range of the engine when the catalyst (,) is in its unheated state, in which its temperature is lower than its activation temperature, and either of the later injection cycle and earlier injection cycle injects fuel which contributes to main combustion during a main combustion period in which approximately 10% to 90% by mass of the injected fuel is burnt in a combustion process occurring in the combustion chamber.