| 摘要 |
A combustion chamber structure for 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. A combustion chamber structure for a direct injection engine is provided with a cavity (11) which is formed and recessed in the center of the top of the piston (10) and 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 longitudinal cross-sectional shape defined by an arc curve which protrudes outward in the radial direction of the piston (10); a bottom wall straight line section (16) which is provided on the bottom wall (14) of the cavity (11) and which has a longitudinal cross-sectional shape defined by a straight line; and a bottom wall gentle curve section (17) which is provided on the bottom wall (14) of the cavity (11) so as to be located between the bottom wall straight line section (16) and the curve section (13) and which has a longitudinal cross-sectional shape defined by a gentle curve having a curvature radius continuously changing from the curvature radius of the arc curve, which defines the longitudinal cross-sectional shape of the curve section (13), to infinite. |
