Blended fuel injection control method for vehicles

A blended fuel injection control method comprising:

• a cold-starting determination step of determining, by a controller, when a cold-starting condition is satisfied on a basis of output values that are configured to be obtained by the controller, wherein the output values are input to the controller by at least one of a water temperature sensor, an oil temperature sensor, an atmospheric temperature sensor, and an altimeter;
• a determination step of determining, by the controller, a content of ethanol in a blended fuel of gasoline and the ethanol when determining that the cold-starting condition is satisfied;
• a first injection control step of controlling, by the controller, the blended fuel to be injected selectively in one of a Multi-Point Injection (MPI) mode, an MPI & Gasoline Direct Injection (GDI) mode combining MPI and GDI modes, and a GDI mode in accordance with the content of the ethanol in the blended fuel until an engine revolution per minute (RPM) reaches a predetermined peak RPM as the engine RPM increases at an early engine staring by engine-cranking;
• and
• a second injection control step of controlling the blended fuel to be injected selectively in one of the MPI mode, the MPI & GDI mode, and the GDI mode in accordance with load periods including a low-load period, a medium-load period, and a high-load period, which are determined by a relationship between the engine RPM and an engine torque, after the first injection control step,
• wherein, in the second injection control step, when the content of the ethanol is a first reference content or more and less than a second reference content, GDI in the low-load period and the medium-load period performs one-step injection and the GDI in the high-load period performs two-step injection,
• wherein, in the one-step injection of the GDI mode, fuel is injected during a predetermined angle within a range of 90° in a retarded direction from a top dead center of a piston in an intake stroke;
• and
• wherein, in the two-step injection of the GDI mode, a first injection of fuel is performed for a predetermined angle within a range of 90° in the retarded direction from the top dead center of the piston in the intake stroke and a second injection of fuel is performed during a predetermined angle from a middle point between a bottom dead center and a top dead center of the piston in a compression stroke.