Abstract
KEYWORDS:
DI diesel engine, intake system, air pressure oscillation, volumetric efficiency, resonance chamber
ABSTRACT:
The periodicity of the engine cycle produces inside the engine's intake system pressure oscillations, which are propagated with the speed of sound. Their shape, amplitude and frequency are dependent on time, engine speed, length of the intake runner, number of cylinders, plenum volume and the wave reflection coefficient at the open end.
In order to maximize the volumetric efficiency, a maximum of the pressure wave's amplitude must be obtained at the time the intake valve closes. This can be achieved through a dynamic tuning of the runner's length and plenum volume to the engine speed, and the engine timing.
Starting from these considerations, the authors have carried out theoretical and experimental researches, on several DI diesel engines, in order to observe the influence of the intake manifold's dimension and configuration on their energetic performances. The results and the limits in which the performances of the DI diesel engines can be improved are synthesized.