Control apparatus and method for direct-injection spark-ignition internal combustion engine

摘要

A control apparatus and method for a direct-injection spark-ignition internal combustion engine in which a stratified combustion is performed to raise an exhaust temperature under a condition prior to a completion of an engine warm-up. The stratified combustion is provided with a lean air-fuel mixture formed over a whole combustion chamber through a fuel injection at a suction stroke and a rich air-fuel mixture formed in an inner space surrounding a spark plug at the combustion chamber through a fuel injection at a compression stroke and a fuel injection quantity of the fuel injection at the suction stroke. A fuel injection quantity of the fuel injection at the compression stroke is corrected by use of a feedback correction coefficient so that an average air-fuel ratio over the whole combustion chamber is controlled to be a predetermined target air-fuel ratio.