Development of optimal diaphragm-based pulsation damper structure for high-pressure GDI pump systems through design of experiments

This study optimizes the profile of the diaphragms of the pressure pulsation damper structure in a high-pressure GDI pump system that is now under development by applying the design of experiments (DOE) method. Because a high-pressure pulsation ranging from 0 to 10bar reduces the performance of a GDI engine and harms it from a structural point of view, attenuating the large amplitude of the fluid pulsation pressure of the gasoline fuel injected into a GDI pump is necessary. Both the relatively low frequency range of the pressure pulsation, i.e., from 0Hz to 30Hz, inside the GDI engine and the high pressure of the utilized gasoline fuel prevent us from applying the existing pressure pulsation dampers such as a T-filter and Helmholtz resonator. Therefore, automotive companies utilize a new pressure pulsation damper structure called an accumulator, which is filled with gas. In the development of this pressure accumulator, it is crucial to design optimal profiles for the enveloping diaphragms in terms of the pulsation efficiency and mechanical stress for the sake of safety. In order to optimize the profile of the diaphragms used in the accumulator developed for a GDI engine, this research develops a new finite element procedure that considers the pressure variation by assuming the isoenthalpy state of the enveloped gas inside the accumulator. The developed finite element procedure is then integrated with the DOE method to determine the optimal profile for the enveloping structure of the developed accumulator. To validate the performance of the developed accumulator, the optimized accumulator is manufactured and tested.