Fluiddynamische Charakterisierung und Verifikation von Dämpfungsmethoden an Common-Rail Einspritzsystemen für Verbrennungsmotoren

In this work dampers to reduce the pulsations that are in the rate of 20 % of the mean system pressure are investigated in detail. For diesel systems NBR as an elastomer offers a potential to minimize the pulsations induced by the high pressure pump by 16 % in tests with the pump only. Dampers made of porous materials reduce the amplitudes in the verified gasoline common rail system up to 60 % depending on the system parameters. The fact of a high pressure drop between the damper and the injector an inline membrane damper is developed. The manufactured prototypes decrease the pulsations up to 75 %. To measure the high dynamic pressure pulsations a diesel and a gasoline common rail was build up. Necessary real time measurements are possible by field-programmable gate arrays (FPGA) and dynamic pressure sensors. Special adapters for the sensors and for implementing the dampers are developed to impact the fluid system as little as possible. Acoustic measurements in the near field of the high pressure pump and the injector of the gasoline system show a maximum decrease of 3,6 dB for the inline membrane damper. In this work a model of porous media for the widespread software AMESim to calculate common rail fluid dynamics is created. Compared to the measurements they show a very good correlation. For future generations of internal combustion engines the analyzed and created dampers can significantly reduce the pressure pulsations. A positive effect for the spray generation into the chamber is expected. So overall the dampers have the potential to increase the efficiency and to reduce the emissions.