Method to inject fuel directly into the combustion chamber of an engine and system comprising a fuel injector and a piston to carry out the method

The method involves defining a combustion chamber (16) by a piston head (7) of a piston (5) and a cylinder tube, and injecting a conical injecting fuel spray with an opening angle between 85 degrees and 140 degrees into a piston bowl (8) provided in the head. The bowl is provided with an omega shaped base form, so that the injected fuel spray is divided into several partial sprays during impingement on a bowl surface (9). An independent claim is also included for a system comprising an injection nozzle and a piston.