In down-sized direct injecting diesel engines, spray impingement on to the cylinder liner during pre-or post-injection is very likely to occur. Therefore the spray behavior before and during the interaction with the wall is of great interest. The goal of the present experiments is to determine the spray behavior for a wide combination of parameters (similar to those of a pre-or post-injection) when interacting with a flat wall. The parameters varied include injection parameters such as injection pressure and timing, as well as in-cylinder parameters such as gas phase pressure, temperature and injector-wall-distance. For these experimental conditions, high speed visualization measurements are performed at about 15 kHz, giving a good impression on the global spray behavior when interacting with a wall. Close to the wall, light-sheet measurements are carried out, which give information onthe inner structure of the spray, such as wall vortices and spray shape. Due to the smaller measurement area, these measurements could be carried out at an increased frame rate of 120 kHz.
Analyzing the spray behavior, a multitude of spray characteristics are evaluated: The free flow velocity, the spray width close to the wall, the temporal evolution of the area of impact, the height of the newly generated spray at the wall and the width of the spray on the wall.