Comparison Between Two Experimental Characterization Setups of Unsteady Behavior of Internal Combustion Engine Intake Systems

In automotive applications, the filling and emptying of internal combustion engine are sometimes analyzed from the frequency spectrum of manifolds. However, this is always established with the assumption of small disturbances which is not realistic in engine ducting, where large pressure fluctuations may arise. For this reason, this paper presents a comparison between the frequency spectrum obtained with the assumption of small disturbances and spectra obtained with a shock test bench. Results of this study show that differences exist. These conclusions are validated by the use of a one-dimensional code which gives the possibility to determine the different parameters which have an influence on the results.