| 摘要 |
<p>PROBLEM TO BE SOLVED: To achieve a high-EGR rate by increasing a recirculation amount of an exhaust gas more than before without causing the generation of black smoke and the deterioration of fuel economy.SOLUTION: In a combustion chamber structure of a direct injection type diesel engine which has a downwardly-recessed cavity 10 at an apex face of a piston 9, radially injects fuel into the cavity 10 from the center of a cylinder ceiling part, and is self-ignited, a step which is recessed to the apex face of the piston 9 at a prescribed depth is formed at an external peripheral part of the cavity 10, a hollow part 20 having a guide face 20a which gradually rises as progressing toward the radial outside, and erects in a recessed face shape is formed, an inlet lip part 22 is formed in a position descended from the apex face of the piston 9 by one stage by an internal peripheral part of the hollow part 20 and a combustion chamber wall face part 21 which erects from a bottom face of the cavity 10, and a shelf part 23 is formed at the external peripheral part of the hollow part 20 by being recessed shallower than the hollow part 20 with respect to the apex face of the piston 9.</p> |
