Plastics fuel tanks

Barrier layer in automotive plastic fuel tanks. 

Fluorination of polyethylene surfaces leads to an increase in the surface energy, some degree of cross-linking and a reduction of the free volume of the polymer. All of these effects impart on the surface of the polymer a barrier that is very impermeable to hydrocarbon solvents. A blow-moulding process, in which a low concentration of fluorine in nitrogen is used as the blow-moulding gas, is used for the production of plastic fuel tanks for the automotive industry (Airopak , Air Products) [51]. Post-treatment of hydrocarbon surfaces with fluorine is an alternative technology and techniques for the surface fluorination of natural and synthetic rubber have been described [52]. 

Plastic Fuel Tank Meets PZEV Regulation (vehicle emission rate), PE, May 2003. 

An alternative approach to the recovery of automotive plastics is therefore to use them as large, easily removable components that offer potential for reclamation as well-characterized individual polymers. Some particularly complex components such as vehicle front- and rear-end systems, exhibit special suitability for manufacture in plastics instead of metals because of their ease of production and assembly. It is generally recognized that improvements in automotive scrapyard economics may be best achieved by the prior removal from vehicles of such large polymeric components and their recycling as well-characterized plastic fractions. For example, plastic fuel tanks of HOPE are now in common use and represent the most common recyclable plastic component. Trials with material recovered from used plastic fuel tanks have shown promising results for the manufacture of new tanks [6]. 

Production of permeation-proof plastic fuel tanks can be realized using coextrusion with mbular die systems, followed up by hollow article extrusion blow molds. Using slit dies, multiple-layer, flat films or plates can be produced, which can then be deep-drawn. When the melt is united before the die, oxidizing gas can be blown into the airstream as an adhesion promoter, or adhesion promoter layers can be extruded into the material by means of coextrusion. Using a rotating mass distributor, sheathing with spiral markings can be made for switch wires, tubes and marbled profiles. 

The history of the plastic fuel tank (PFT) provides a perfect example of competition among different materials to meet product requirements. 

A crucial point in the safety of motor vehicles is the testing of plastics fuel tanks, which have been gaining ground rapidly in the last few years. The relevant tests were developed in the FRG by the Special Committee of Transportation Technique, Sub-Committee of Fire Safety (Fachausschuss Kraftfahrtechnik, Sonderausschuss... 

Eollowing the success story of the plastic bumpers, for automobiles, which commercially replaced the heavy metallic bumpers, the plastic fuel tanks are making inroads to replace metallic fuel tanks. The plastic tanks offer weight reduction, freedom from corrosion, and ease of fabrication. 

Various approaches have been suggested to reduce the number of fires at petrol filling stations caused by static electricity. One suggestion is metal door handles. Conducting additives are used to provide static dissipation in fuel systems, but there are difficulties in achieving adequate mechanical properties in polyethylene fuel tanks when carbon black is used as a filler. Doubts have also been raised in some quarters about whether some plastic fuel tanks will be able to meet the requirements for PZEVs , or partial zero emissions vehicles, required by California s new emission standards. Inergy Automotive recommends capless filler systems with locking mechanisms. Carbon nanotubes are likely to find a role in antistatic protection. 

Y Kurihara, K Nakazawa, K Ohashi, S Momoo and K Numazali, Development of multi-layer plastics fuel tanks for Nissan research vehicle . 

Plastic Fuel Tank Bladder Cuts Explosion Hazard. Plastics World, p. 22, Mar. 1990. 

Figure 16 Typical example of a modern multilayer plastics fuel tank.

With this method, the extruder also works continuously, but the melt is stored in a tubular piston accumulator (Figure 1.139) from which the plastic is intermittently extruded to produce the tubular preform. Figure 1.140 illustrates an extrusion blow molding machine equipped with an accumulator head as it is used, for example, in the manufacture of plastic fuel tanks, barrels, liners, and other similar large structures. The removal of the finished part is done with grippers and a transfer mechanism. The accumulator heads work best with the first in, first out (FiFo) principle. This is necessary in order to accommodate for the limited thermal stability of the plastic. 

FIGURE 1.151 Blow mold for plastic fuel tank... 

FIGURE 1.156 Stainless steel cooling cage for plastic fuel tank blow mold in which areas of sliders and mold inserts are circumvented... 

Table 30.15 European Standards for Plastic Fuel Tanks [106]...

Ustaoglu HB, Ayhiin S, Simitgioglu G, Siisler S, Akay E, Dogan VZ, et al. Static and dynamic analysis of plastic fuel tanks used in buses. ProcediaEng 2015 101 509-17. 

ACC. Plastic fuel tanks can decrease vehicle weight and incidence of corrosion. Washington, DC American Chemistry Council 2008. 

Plastic fuel tanks are now in common use, and an investigation has been made of some possibilities for the recycling of the materials used in them. The project comprises of four stages ... 

Stage 4 will involve the recycling of used plastic fuel tanks on an industrial scale. 

The material used for the investigation was obtained from Volkswagen Golf and Passat vehicles, which have employed plastic fuel tanks for some 10 years. The time required for tank removal, cleaning, and elimination of tank components, made either of metal or a plastic other than HDPE, averaged some 5 min 30 sec. At a labour cost of DM 45/h this implies some DM 4.2 for recovery of a fuel tank 3nelding 3.8 kg of HDPE with, at a price of about DM 1.8/kg for secondary HDPE, a nominal value of DM 6.9. 

The moduli of elasticity of samples made from recovered material were much higher than those made from unused tanks. Though perhaps partially attributable to cross-linking, it is more hkely to reflect a change of specification of the Lupolen 4261A, whose modulus of elasticity was in 1978 given as 1200 N/mm and in 1989 as 850 N/mm. The higher value of the modulus of elasticity does not necessarily constitute a poorer quality of material so far as the requirements of plastic fuel tanks are concerned. 

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