Patent ID: 6892695
Filing Date: 2005-05-17
Classification: F02B,F02F,Y02T

Abstract:
1. Combustion process with charge stratification for an internal combustion engine having direct injection and spark ignition, the engine having a cylinder, the cylinder having a roof-like border on a cylinder head end containing intake valves and at least one exhaust valve, and a piston, the piston having a piston head adapted to the roof-like border with a recess oriented to a side of the cylinder containing at least one of the intake valves, comprising the steps of: introducing charging air during a stratified charge operation through one of at least two intake valve-controlled intake channels into the cylinder to create a swirl flow the vicinity of the recess; introducing fuel into the swirl flow from an injector nozzle; and igniting the fuel with an ignition device located at a top center of the roof-like border, wherein the recess is essentially open at an intake side and has a recess border on a side opposite the intake side of up to 0.15 D high and up to 0.2 D from the center axis of the ignition device, where D is a cylinder diameter, the intake valve controlling the intake channel through which charging air is introduced is operated essentially unthrottled at least in stratified charge operation, and an injector nozzle located between the intake channels and a top of a cylinder wall delivers fuel in a spray cone in the direction of the ignition device, the spray cone having a stream axis inclined 0 and 30 degrees downward from a plane orthogonal to the cylinder axis, the injector nozzle being controllable as a function of load such that a substantial portion of the spray cone is introduced into the swirl core, such that a tubular swirl core aligned with a center axis of the ignition device is formed from the swirl flow by the recess by the time the piston is between 60 degrees and 30 degrees before top dead center, and an ignitable mixture cloud formed in the swirl core is held in the area of the ignition device while the piston approaches top dead center.