Direct fuel injection type spark ignition internal combustion engine having a squish flow for assisting fuel evaporation

A direct fuel injection type spark ignition internal combustion engine comprising:

• a piston/cylinder structure including a cylinder, a piston reciprocally movable in the cylinder, and a cylinder head, wherein fuel is directly injected into the cylinder onto a surface of one of the piston and the cylinder head, the fuel adhering to the surface being evaporated at the surface by heat at the surface and being assisted in evaporation by an air flow generated in the cylinder, the evaporated fuel subsequently being ignited;
• a squish portion defined between two squish portion defining surfaces that include one portion of an upper surface of the piston and one portion of a lower surface of the cylinder head and are located in one half cross-section of the cylinder, the squish portion generating a squish flow as the air flow in the cylinder for assisting fuel evaporation when the piston is moved near a top dead center, the squish portion having a closed end defined by one portion of an inside surface of the cylinder and an open end opening in a direction toward a center of the cylinder, the squish portion being enlarged in the direction toward the center of the cylinder so that a central portion of the open end of the squish portion is located adjacent to the center of the cylinder;
• a fuel injector for injecting fuel located adjacent to a central portion of the closed end of the squish portion, the fuel injector being directed so as to inject at least one portion of the fuel onto one of the squish portion defining surfaces so that the fuel adhering to the one squish portion defining surface is assisted in evaporation by the squish flow;
• and
• a spark plug located adjacent to the center of the cylinder so as to oppose the central portion of the open end of the squish portion, the spark plug igniting the evaporated fuel blown toward the spark plug by the squish flow.