DIRECT FUEL INJECTION DIESEL ENGINE

摘要

A direct fuel injection diesel engine having a pent roof-type piston. The piston (13) has a cavity (25) recessed at its center, and the height of the top surface of the piston (13) varies in the circumferential direction. The cavity (25) is defined by first to third specific points (An, Bn, Cn) on fuel injection cross-sections (S2). A fuel injection cross-section (S2) is that cross-section of the cavity (25) that passes each fuel injection axis (Li2) along which fuel is injected from a fuel injection point (Oinj) of an injector placed on the center axis of the piston. The shapes (see the shaded portions) of the fuel injection cross-sections (S2) are set such that they are substantially equal to each other. The construction uniformizes mixing of air and fuel in each fuel injection cross-section to enhance the engine output and reduce harmful components in exhaust gas.