Fuel injection system

The fuel injection system (1) includes a fuel injection valve (7) injecting fuel into a combustion chamber (6) bounded by a cylinder wall (2), within which is a piston (3) and a spark plug (8). A conical injection jet (13) is created. The piston recess (12) and piston surface (15) are shaped to produce restricted flow between the piston and the cylinder head in the direction of the injection valve.