Self-igniting internal combustion engine with a rotationally symmetrical piston trough

Self-igniting internal combustion engine with a rotationally symmetrical piston trough exhibiting in cross section a flat bottom well rounded at the rim and conical sidewalls, and

• wherein the inlet opening is smaller than the largest diameter of the piston trough, and with an injection nozzle injecting into the piston trough so that the walls are wetted, characterized by the combination of the following features:
• (a) the diameter of the inlet opening is about 0.35-0.43 times the piston diameter, and the total depth of the piston trough is about 0.6-0.8 times the diameter of the inlet opening;
• (b) the angle of conicity of the sidewalls is about 7-15.degree.;
• (c) a continuously extending, projecting annular bead formed, in cross section, by two bead flanks converging approximately at a right angle is provided in the transition zone between the sidewall and the bottom, the annular bead flank of this annular bead facing the inlet opening lying, in cross section, approximately in parallel to the piston crown, and the continuously extending rim of this annular bead extending in parallel to the piston crown;
• (d) the axial spacing of the plane of the annular bead flank from the bottom of the piston trough corresponds approximately to 12-33% of the total depth of the piston trough;
• (e) the diameter of at least one annular bead flank corresponds approximately to 0.9-1.1 times the diameter of the inlet opening;
• (f) the annular bead flank facing the bottom of the piston trough passes over, in cross section, with a radius of about 22-35% of the total depth into the bottom and the annular bead flank facing the inlet opening passes over, in cross section, with a radius of about 2-5 mm into the sidewall;
• (g) the injection nozzle, arranged eccentrically to the piston trough but still within the inlet opening thereof, directs its jets onto the sidewall of the piston trough in such a way that the point of impingement of the injection jets lies axially approximately in the center between the annular bead rim and the piston crown.