The protrusion between inlet valve seat machining surface and combustion chamber casting surface effects tumble ratio of high BTE (>40%) GTDI engine flow box. Tumble ratio could increase by appropriate step, and decrease by higher or lower step. CFD results show that protrusion machined by one-process can get better tumble ratio than two-processes. Using FEV evaluation methodology, some variants were taken into this research, upper tolerance (+0.36 mm) step shows nearly same charge motion level like nominal flow box (+0.1 mm) and reaches only slightly lower first tumble peak, bottom tolerance (−0.16 mm) step shows lower first tumble peak but at second tumble peak difference are small. All designs in the tolerance reach the same TKE around spark plug at igniting time. It’s a very low and similar wall film level for all steps in the range of tolerance. At last, two prototype cylinder head samples with +0.1 mm and +0.25 mm step were tested on AVL flow test bench. The result shown that the tumble ratio of +0.1 mm step increase 4.3%, but coefficient flow decreases 3.3%, following with CFD result trend.
Study of Inlet Valve Seat Protrusion Effect on GTDI Engine Flow Box
Lect. Notes Electrical Eng.
2022-01-13
13 pages
Article/Chapter (Book)
Electronic Resource
English
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