| 摘要 |
A combustion chamber structure of a direct injection engine is configured in such a manner that smoke, NO, and the like are reduced by a simple change in the shape of a cavity. The combustion chamber structure of a direct injection engine includes a cavity (11) recessed in the center of the top of the piston (10) into which fuel is injected from the injector disposed above the piston (10). The cavity (11) includes a curve section (13) which is provided on the lower part of the side wall (12) of the cavity (11) and which has a vertical cross-sectional shape defined by an arc protruding outward in the radial direction of the piston (10). The cavity also includes a bottom wall straight line section (16) which is provided on the bottom wall (14) of the cavity (11) and which has a vertical cross-sectional shape defined by a straight line. The cavity also includes a bottom wall transition curve section (17) which is provided on the bottom wall (14) of the cavity (11) between the bottom wall straight line section (16) and the curve section (13) and which has a vertical cross-sectional shape defined by a transition curve having a curvature radius continuously changing from the curvature radius of the arc, which defines the vertical cross-sectional shape of the curve section (13), to an infinite value. |
