CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

An object of the present invention is to provide a control apparatus for an internal combustion engine that can prevent reliably an external EGR gas amount from being uneven among cylinders during performance of external EGR and prevent deposits from being deposited in an intake manifold. The control apparatus for an internal combustion engine of the present invention includes fresh air backflow control means. The fresh air backflow control means performs fresh air backflow control that causes part of fresh air drawn into a cylinder to flow back into an inside of the intake manifold by operating, when external EGR is to be started, a variable intake valve actuating device such that intake valve closing timing is retarded relative to that before the external EGR is started. The backflow of the fresh air sufficiently mixes external EGR gas inside the intake manifold with the fresh air to establish a uniform mixing ratio, so that an amount of external EGR gas flowing into cylinders can be equalized. In the fresh air backflow control, fresh air instead of internal EGR gas (burned gas) flows back into the intake manifold. Thus, deposits can never be deposited.