Internal combustion engine control device

Abstract

In an internal combustion engine which performs a homogeneous lean combustion mode and a stratified lean combustion mode, there is provided a new internal combustion engine control device capable of obtaining a stable combustion state by decreasing influences of delay of an air flow and a degree of change of a transient state and smoothly performing switching between the homogeneous lean combustion mode and the stratified lean combustion mode. Accordingly, in the present invention, when switching between the stratified lean mode in which a compression stroke injection is performed by a direct injection injectorand the homogeneous lean combustion mode in which an intake stroke injection is performed by the direct injection injectoris performed, a predetermined delay time Δt is provided from at least a switching operation of a tumble control valve, a switching operation between the compression stroke injection and the intake stroke injection is performed, and the delay time Δt is set so as to correspond to a magnitude of the degree of change ΔL of the transient state. A switching timing between the compression stroke injection and the intake stroke injection is controlled according to the flow delay of an air control system such as the tumble control valveand the degree of change ΔL of the transient state, and thus, it is possible to improve combustion stability in a combustion chamber.