The paper illustrates the employment of both numerical and experimental methodologies to characterize performances and overall noise radiated from a common rail light duty diesel engine.
An experimental investigation was preliminarily carried out to compare the behavior of the engine, equipped with two different injection systems: an under development low-cost fuel injector and a commercial Bosch one, employed for automotive applications. Both engine performances, pollutant and noise emissions were measured at different operating conditions for two injection strategies (single injection and pilot plus main injection). Concerning the acoustic analysis, both structure born and gasdynamic noise contributions were estimated using different experimental techniques.
Contemporarily to the above campaign, a one-dimensional simulation of the investigated engine was performed, too. modeFRONTIER code was employed to carefully tune the combustion sub-model included in the one-dimensional simulation code (GT-Power). The tuning process provided some information on the spray combustion and heat release realized by the two fuel injection systems (FIS). The numerical results were then compared to the experimental ones, in terms of heat release fraction, in-cylinder pressure signal and gasdynamic noise emissions.
Finally, the tuned 1D model was coupled to modeFRONTIER code to find the injection strategy realizing the best trade-off between performance and emission. A redesign of the intake system was also carried out to reduce the gasdynamic noise contribution.
The results pointed out how the integration of different methodologies can improve engine performances and reduce noise emissions. |
