Low Permeation Technologies For Plastic Fuel Tanks 2003-01-0790
Plastic materials are used for fuel tanks for automobiles because they are lightweight and highly durable and help these tanks ensure a capacity. However, plastic fuel tanks have the disadvantage of easily allowing the fuel to permeate through.
To solve this problem, HDPE is used nowadays as the main material, and fuel tanks using EVOH for a barrier material and formed by multi-layer blowing are installed in the majority of automobiles conforming to the Tier 1 regulations set by EPA and the LEV I regulations set by CARB. In view of EPA's Tier 2 regulations and CARB's LEV II regulations, both of which will be launched in the near future, plastic fuel tanks with a lower level of fuel vapor permeability (hereinafter referred to as “permeability”) are desired.
We thus developed a plastic fuel tank that is much lower than conventional plastic fuel tanks in permeability. This low-permeation plastic fuel tank may easily conform to the Tier 2 and LEV II regulations.
This paper outlines the main low permeation technologies for the plastic fuel tank we developed, and describes, among them, a low permeation technology for joints.