An internal combustion engine system includes an internal combustion engine including a cylinder, an intake valve and an exhaust valve, a cylinder injection valve, and a variable valve drive mechanism, and a control device that controls the cylinder injection valve and the variable valve drive mechanism. The control device includes a calculation unit that calculates a first crank angle section where a temperature of the cylinder is equal to or higher than a boiling point of the fuel in a compression stroke before completion of warming-up of the internal combustion engine and a second crank angle section where the temperature of the cylinder is equal to or higher than the boiling point of the fuel in the valve closed period, and an injection controller that executes fuel injection in the first and second crank angle sections by the cylinder injection valve.

A method for controlling an internal combustion engine system including a catalyst includes receiving a desired output for an internal combustion engine, and receiving sensor information including information indicative of a temperature of the catalyst. The method includes calculating a plurality of sets of engine performance values based on respective sets of candidate control points, the engine performance values including a temperature change rate at which the temperature of the catalyst changes over time, and determining whether the temperature change rate satisfies a minimum warmup rate for the catalyst. The method also includes controlling the internal combustion engine based on a selected set of candidate control points and the minimum warmup rate.

A method for controlling an internal combustion engine system including a catalyst includes receiving a desired output for an internal combustion engine, and receiving sensor information including information indicative of a temperature of the catalyst. The method includes calculating a plurality of sets of engine performance values based on respective sets of candidate control points, the engine performance values including a temperature change rate at which the temperature of the catalyst changes over time, and determining whether the temperature change rate satisfies a minimum warmup rate for the catalyst. The method also includes controlling the internal combustion engine based on a selected set of candidate control points and the minimum warmup rate.