An advanced hybrid electric cross-over vehicle, the 2010 Lexus RX 450h features a sealed steel tank that requires structural resistance to high internal pressure. Conventional plastic tanks cannot meet the high internal operating pressures. With a mass of 30 kg (66 pounds), the low-carbon steel tank has 2 mm / 0.079 inch thick walls and meets high internal pressure. The flat shaped steel tank is resistance seam welded tank and has a 16 gallon fuel capacity (60 liters).
Supplied by Nippon Steel, the steel is hot dip tin zinc painted after tank assembly.
The high mass of current-generation sealed steel tanks has been addressed in a 2011 study by the Strategic Alliance for Steel Fuel Tanks (SASFT) and in a collaborative study between SASFT and the United States Advanced Materials Program (USAMP). Both studies have shown that significantly lower masses can be achieved using thinner advanced high-strength steels together with structural enhancers such as stiffening ribs and structural internal buffers baffles. These techniques offer an approach for producing low-mass sealed steel tanks (equivalent mass to conventional unsealed tanks) for future advanced hybrid electric vehicles.
The Strategic Alliance for Fuel Tanks (SASFT) is an international alliance of companies specializing in the various areas of fuel tank production, possessing a common interest in the development, optimization and application of steel fuel tanks for automobiles. SASFT was organized by the American Iron and Steel Institute in 2000 to bring together the diverse business disciplines involved in designing, manufacturing and supplying steel fuel tanks in the automotive market. For more information on SASFT, please visit www.sasft.org.