No abstract

New and increasingly strict emission standards demand a reduction in the raw emissions from today's gasoline direct injection engines. The optimisation of mixture formation by means of the injector and, in particular, the injector hole geometry offers significant potential in this respect. To achieve this, however, it is crucial to have a basic understanding of the influence of the geometry on spray breakup. To investigate this influence, a test matrix with ten different injector hole geometries was created. This included cylindrical, convergent, divergent and stepped injector holes. Different measuring techniques were used to analyse the microscopic and macroscopic spray parameters as well as the internal flow in the nozzles.