Optimal Design of Type 2 High Pressure Vessel for CNG Vehicles

Abstract Compressed Natural Gas (CNG) pressure vessels are used for fuel storage in eco-friendly vehicles, providing a safe fuel supply under high pressure. Lightweighting of CNG pressure vessels while ensuring structural safety is an essential factor. In this study, liner and composite thickness designs were performed to reduce the weight of CNG pressure vessels. The stress behavior based on liner and composite thicknesses was analyzed using the commercial finite element analysis software, ANSYS Workbench. To improve fatigue life and durability, considering failure due to buckling and burst, autofrettage pressure was applied. Using optimal design, a minimum-weight pressure vessel was achieved, meeting criteria for structural safety, fatigue life, and cost reduction. Therefore, a 6.6% reduction in weight was achieved compared to CNG pressure vessels currently manufactured in the field.