Patent ID: 7395806

Claim:
A reciprocating internal-combustion engine having at least two gas intake ports ( 3 ) with gas intake valves ( 6 ), at least one gas exhaust port ( 4 ) with a gas exhaust valve ( 7 ) and at least one ignition device ( 14 ) per cylinder ( 1 ), and having a combustion chamber ( 1 . 1 ) formed by the cylinder cover ( 2 . 1 ) and the crown ( 11 . 1 ) of the piston ( 11 ), which is guided in the cylinder ( 1 ) in a reciprocating manner, into which combustion chamber the gas intake ports open at a flat angle, measured in relation to the cylinder-head plane ( 2 . 1 ), wherein the piston crown ( 11 . 1 ) on the one hand and the cylinder cover ( 2 . 1 ) on the other hand are substantially roof-shaped in vertical section, wherein in each case one of the roof surfaces is associated with the gas intake valves ( 6 ) and the other roof surface is associated with the gas exhaust valve ( 7 ), and the orientation of the roof surfaces of the cylinder cover ( 2 . 1 ) corresponds to the orientation of the roof surfaces of the piston crown ( 11 . 1 ), and having a fuel injection nozzle ( 8 ) opening into the cylinder ( 1 ) near the inlet region of the gas intake ports ( 3 ) between the gas intake valves ( 6 ), wherein, measured in relation to the cylinder axis ( 5 ), the angle of the jet axis ( 9 ) of the fuel injection nozzle ( 8 ) is greater than the angle of the gas intake ports, and having an ignition device ( 14 ) arranged in the cylinder cover ( 2 . 1 ) close to the cylinder axis ( 5 ), and having a trough-shaped recess ( 12 ) which is provided in the piston crown ( 11 . 1 ) and is bounded by a trough base ( 12 . 1 ) and side walls ( 16 ) and which intersects the roof ridge ( 11 . 2 ) on the piston crown and extends over the region of both roof surfaces, the trough base ( 12 . 1 ) slopes towards the fuel injection nozzle ( 8 ) and ending in a wall zone ( 12 . 2 ) extending steeply upwards on its side facing the fuel injection nozzle ( 8 ), wherein the transition region ( 15 ) between the trough base ( 12 . 1 ) and the side walls ( 16 ) has a substantially barrel-shaped contour in plan view, which first widens on both sides from the gas exhaust side ( 4 ) and then narrows again towards the gas intake side, one end of which is formed by the wall zone ( 12 . 2 ) extending steeply upwards.