Patent ID: 6378486
Filing Date: 2002-04-30
Classification: F02B,F02F,Y02T

Abstract:
A four-stroke internal-combustion engine with spark ignition, comprising: a combustion space; an injection nozzle operatively arranged so as to directly inject fuel into the combustion space; at least one inlet duct having an inlet valve; at least one outlet duct having an outlet valve, the inlet valve and the outlet valve being arranged on opposite sides of the combustion space, the injection nozzle being arranged on an inlet-valve side of the combustion space; and a piston having a longitudinal center axis extending in a direction of movement of the piston, the piston having a piston head with at least one recess arranged on the inlet-valve side and being designed, with respect to the inlet valve and the injection nozzle, with at least one edge portion of a circumferential contour forming a highest point of the piston head, so that an airflow enters the combustion space from a correspondingly designed inlet duct via the inlet valve and an injection jet enters the combustion space from the injection nozzle into the recess on opposite sides, the piston head further having an elevation that divides the recess into a fuel recess and an air recess transversely to the injection direction so that the injection jet enters the fuel recess on a side located opposite the elevation and the airflow enters the air recess, in a direction opposite to the injection jet, on a side located opposite the elevation, the fuel recess being configured to have a depth tKa, in a sectional plane, between the elevation and a lower fuel-recess edge of 4 mm to 12 mm, the air recess being configured to have a depth tL, in the sectional plane, with respect to an air-recess edge located opposite the elevation of 2 mm to 10 mm, the fuel recess being further configured so that a tangent of a fuel-recess wall at a fuel-recess edge located opposite the elevation forms with the longitudinal center axis an angle &ggr;K1 of 40 degrees to 62 degrees, the air recess being further configured so that a tangent of an air-recess wall at a fuel-recess edge located opposite the elevation forms with the longitudinal center axis an angle &ggr;L of 30 degrees to 62 degrees.