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The Influence of Cylinder Head Geometry Variations on the Volumetric Intake Flow Captured by Magnetic Resonance Velocimetry
Abstract:
Magnetic Resonance Velocimetry (MRV) measurements are performed in 1:1 scale models of a single-cylinder optical engine to investigate the differences in the inlet flow due to geometrical changes of the cylinder head. The models are steady flow water-analogue of the optical IC engine with a fixed valve lift of 9.21 mm to simulate the induction flow at 270° bTDC. The applicability of MRV to engine flows despite the differences in experimental operating parameters between the steady flow model and the optical IC engine are demonstrated and well addressed in this manuscript and in a previous work [1]. To provide trust into the MRV measurements, the data is validated with phase-averaged particle image velocimetry (PIV) measurements performed within the optical engine.
The main geometrical changes between the cylinder heads include a variation of intake valve diameter and slight modifications to the exit of the intake port. The MRV measurements reveal significant changes in the velocity distribution within the overflow and underflow region of the intake valves for the two cylinder head designs. These changes produce contrasting flow entrainment patterns into the cylinder, which support evidence of different flow generated patterns captured by PIV during the intake and compression stroke.
The model generation, performed using selective laser sintering, allows easy geometrical variations and the MR-scanner enables low acquisition time and automated post-processing. MRV is revealed to be a suitable diagnostic tool to understand the volumetric induction flow within engine geometries and to evaluate flow changes due to geometrical variations of the engine.