Low-cost conformable storage to maximize vehicle range
Liquefied petroleum gas (LPG) and compressed natural gas (CNG) are currently the leading fuel contenders for converting vehicles from gasoline and diesel to alternative fuels. Two factors that inhibit conversion are additional vehicle costs and reduced range compared to gasoline. In overcoming these barriers, a key element of the alternative fuel system becomes the storage tank for these pressurized fuels. Using cylindrical pressure vessels is the conventional approach, but they do not package well in the available vehicle volume. Thiokol Corporation has developed and is now producing a conformable (non-cylindrical) aluminum storage system for LPG vans. This system increases fuel storage in a given rectangular envelope. The goal of this project was to develop the technology for a lower cost conformable tank made of injection-molded plastic. Much of the cost of the aluminum conformable tank is in the fabrication because several weld seams are required. The injection-molding process has the potential to greatly reduce the fabrication costs. The requirements of a pressurized fuel tank on a vehicle necessitate the proper combination of material properties. Material selection and tank design must be optimized for maximum internal volume and minimum material use to be competitive with other technologies. The material and the design must also facilitate the injection-molding process. Prototype tanks must be fabricated to reveal molding problems, prove solutions, and measure results. In production, efficient fabrication will be key to making these tanks cost competitive. The work accomplished during this project has demonstrated that conformable LPG tanks can be molded with thermoplastics. However, to achieve a competitive tank, improvements are needed in the effective material strength. If these improvements can be made, molded plastics should produce a lower cost tank that can store more LPG on a vehicle than conventional cylinders.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Energy Efficiency and Renewable Energy, Washington, DC (United States)
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 567485
- Report Number(s):
- NREL/SR-540-23579; ON: DE98002694; TRN: 98:001060
- Resource Relation:
- Other Information: PBD: Jan 1998
- Country of Publication:
- United States
- Language:
- English
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