Patent ID: 7987043
Filing Date: 2011-07-26
Classification: F02D,Y02T

Abstract:
1. A fuel injection control apparatus for an internal combustion engine, which is applied to an internal combustion engine that includes a fuel injection valve that injects fuel from an inside of an intake passage toward a combustion chamber in each cylinder, the control apparatus comprising: a control section, wherein the control section controls fuel injection from the fuel injection valve for each cylinder after a crank angle is determined through cranking for starting the engine, in a fuel injection mode in which an amount of the fuel present in the combustion chamber when the fuel in the combustion chamber is to be combusted in each cylinder after the crank angle is determined is brought to a value required to start the engine, wherein in the internal combustion engine, after the crank angle is determined, the fuel in an amount corresponding to a start-up injection amount command value, which is calculated as a fuel injection amount required to start the engine based on an engine temperature and an alcohol concentration in the fuel, is injected from the fuel injection valve for each cylinder in a determined fuel injection mode, wherein the cylinders of the internal combustion engine are grouped into a front stroke cylinder group that includes the cylinders in which the fuel in the amount corresponding to the start-up injection amount command value is injected by an early stage of a first valve opening period of an intake valve after the crank angle is determined, and a back stroke cylinder group that includes the cylinders in which the fuel in the amount corresponding to the start-up injection amount command value cannot be injected by the early stage of the first valve opening period of the intake valve after the crank angle is determined, wherein the control section newly sets a fuel injection mode for high alcohol concentration as a fuel injection mode in which an amount of the fuel present in the combustion chamber when the fuel in the combustion chamber is to be combusted in each cylinder after the crank angle is determined in a state where the alcohol concentration in the fuel is high is brought to a value required to start the engine, wherein the fuel injection mode for high alcohol concentration is improved grouped injection in which, after the crank angle is determined, in the cylinders of the front stroke cylinder group, fuel injection is started so that the injection of the fuel in the amount corresponding to the start-up injection amount command value is completed by the early stage of the valve opening period of the intake valve, and in the cylinders of the back stroke cylinder group, injection of the fuel in an amount corresponding to a start-up injection amount command value, which is corrected to a value larger than the start-up injection amount command value that is used for the fuel injection in the cylinders of the front stroke cylinder group, is started at the same timing as the fuel injection in the cylinder of the front stroke cylinder group, in which a piston is in the same position as that in the cylinder of the back stroke cylinder group, and wherein when the alcohol concentration in the fuel is high, the control section shifts the fuel injection mode after the crank angle is determined to the fuel injection mode for high alcohol concentration, and the control section controls fuel injection from the fuel injection valve for each cylinder after the crank angle is determined in order to achieve the fuel injection mode for high alcohol concentration.