Method of operating a diesel i.c. engine having intake air swirl control means

In a method of operating a diesel internal combustion engine (1), a homogeneous mixture is formed in the combustion space (4) no later than the time of spontaneous ignition by means of fuel injected directly and separately supplied combustion air. In order to achieve very low pollutant emissions and an improvement in the efficiency of the internal combustion engine in combination with homogeneous mixture formation, the combustion air is admitted to the combustion space (4) in a swirling flow (14) about a longitudinal axis (19) of the cylinder (2) that can be adjusted as regards its swirl intensity by means of a control element (11). A control unit (17) adjusts the swirl intensity in a manner coordinated with the injection parameters for the process of fuel metering. The control unit 17 controls the common rail fuel injector 5, the swirl control element 11 and RGR valve 9 in response to signals representing fuel quantity injected (L1), engine speed (L2) and mass flow of intake air from sensor 12. The fuel may be injected as a main injection, between 40 degrees before TDC to 20 degrees after TDC, and a smaller post-injection.