Fuel injection system for a mixture-compressing spark ignition internal-combustion engine

A fuel injection system for a mixture-compressing spark ignition internal-combustion engine has a fuel-metering device having a housing with a control cylinder arranged therein, a control piston having at least two control edges being rotatably and longitudinally slidably arranged in said control cylinder. One front surface of said control piston is acted upon by fuel and its other front surface interacts with a pressure spring. Between the control edges, the control piston is equipped with a control space area. The housing has an inflow opening for a fuel inflow pipe, an outflow opening for a fuel return flow pipe in which a pressure regulating valve is arranged, and an outflow opening assigned to a fuel injection nozzle. The outflow opening connected with a control opening in the control cylinder interacts with the control edges. The control space area has at least one recess at the control piston having a circular-arc-shaped area segment forming the control edges in order to provide a fuel injection system having a fuel-metering device of the initially mentioned type which is simple to manufacture and easy to assemble, exhibits high operational reliability and ensures an exact metering of fuel. The axis of said area segment extends transversely to the control piston axis and starts from the circumferential area of the control piston in a concavely curved manner extends into the control piston. The control piston has an axial flow-through bore equipped with a throttle downstream from the recess. The fuel passes through said flow-through bore from the inflow opening of the housing to the recess and to the outflow opening of the housing.