In the paper the results of the research on CI direct injection combustion engines with partial homogenisation of the cylinder charge have been presented. Based on the research needs in the development of injection and combustion systems in modern engines, particularly in the range ofstratification of the charge andflame propagation optical investigation methods have been chosen for the detailed studies. The endoscopic observations of the injection, self ignition and combustion processes have been carried out and a numerical analysis of the observation results has been evaluated and discussed. The observations carried out in the combustion chamber on running engines allowed the estimation of the flame propagation and the flame temperature distribution in the combustion chamber. Research has been executed for a variety of cylinder charging pressures and for different fuelling systems: conventional and with partial homogenisation of the charge. Some conclusions concerning problems of the flame structure and its propagation in the combustion chamber with partial homogenisation of the charge in comparison to the conventional system have been formulated.