TEST BED INVESTIGATION OF THE SI ENGINE WORKING ON HETEROGENIOUS MIXTURE

摘要

The paper investigates the demonstration of the increase in total efficiency of a GDI engine in dependence on the parameters of mixture formation and the range of load at determined states of engine work in dependence on the rotational speed of the engine. By use of the newest simulation programme KIVA 3V, the possibilities of up-to-date methods of calculation of changes of temperatures, pressures, and the formation of toxic components during the process of stratified charge combustion were presented. The elaborate mathematical models, used in calculations, describing the processes occurring inside the cylinder of the engine, permit one to create complicated virtual models reflecting the real conditions in a satisfactory way. The correctness of calculation results is determined by the quality of input data, which can be obtained based on model investigations. In the experimental section, investigations on a test bed with use of specialist apparatus for visualisations of inside cylinder processes were discussed. By use of visualisation, observation was performed of the run of the fuel jet from the moment of injection, consequent by rebounding of the fuel from the piston head, on to reaching under the gap between the electrodes of the ignition plug and flame spreading from the moment of ignition till the end of the combustion process. For the determination of the total efficiency of a Gasoline Direct Injection engine, test bed investigations were carried out with the aim of determining the speed and load characteristics of the investigated engine. On this basis, the total efficiency of a GDI engine can be determined.