In order to clarify certain aspects of the combustion process in differentially cooled engines, a special engine was built in which the surface temperatures of the piston crown, cylinder liner and cylinder head bottom could be varied independently. A computer programme to calculate the swirl and turbulence intensity in the combustion chamber was developed. Investigations showed that in order to improve the mixing process, the liner temperature should be kept low while the piston temperature may be increased only if the cylinder head temperature is kept low, and vice versa. A low coefficient of regression in the plotted results indicated that the flow parameters Investigated were not the determining parameters but only one among many others which need further investigation. The present investigation however Indicates that the high piston temperature found desirable earlier should preferably be combined with low cylinder head and liner temperatures.