Abstract: A method for operating a spark-ignition direct-injection internal combustion engine coupled to an exhaust aftertreatment system including a catalytic converter includes monitoring an operating state of the catalytic converter. The method further includes determining if a piston of the engine is entering an intake stroke. The method further includes injecting a first quantity of fuel into a cylinder in which the piston of the engine is entering the intake stroke, and injecting a second quantity of fuel into the cylinder in which the piston of the engine is entering the intake stroke.

Abstract: A method for operating a spark-ignition direct-injection internal combustion engine coupled to an exhaust aftertreatment system including a catalytic converter includes monitoring an operating state of the catalytic converter. The method further includes determining if a piston of the engine is entering an intake stroke. The method further includes injecting a first quantity of fuel into a cylinder in which the piston of the engine is entering the intake stroke, and injecting a second quantity of fuel into the cylinder in which the piston of the engine is entering the intake stroke.

Abstract: An internal combustion engine adapted for combustion of stoichiometric and non-stoichiometric air/fuel mixtures includes an intake system, a combustion chamber which is adapted for direct injection of a fuel and an exhaust system. The intake port flow output comprises an intake airflow output and an EGR airflow output. An intake port flow estimator determines an intake port gas flow output from the intake mass airflow input of the intake airflow into the intake manifold and the EGR mass airflow input of the EGR airflow of the EGR airflow into the intake manifold using a plurality of engine parameters and an air/fuel adjustment factor. The intake port gas flow output is determined as an effective intake airflow output and an effective EGR airflow output. The effective intake airflow output to the combustion chamber is used to determine an effective mass of intake air output per cylinder.