Blow-molded based plastic fuel system technology offers the perfect balance between safety, weight and cost for automotive fuel applications. The use of plastics for fuel systems allows for:
- Weight reduction, thus better fuel economy and lower CO2 emissions: an average plastic tank weighs one-third less than an average steel tank.
- Tank durability and biofuels compatibility: plastic fuel tanks made of high-density polyethylene (HDPE) are corrosion-resistant without any need of special coatings, making it also compatible with all kinds of bio-fuels. In addition, HDPE can help dissipate electrostatic charge and prevent igniting fuel. Also, several studies demonstrated the superiority of plastics in terms of Life Cycle Assessment.
- Design freedom allowing space economy: Thanks to the flexibility of this material, fuel tank systems made of plastics can be designed to fit the exact given space on the car chassis, thus increasing fuel storage capacity.
- Noise attenuation: insulating properties of plastics allow to reduce fuel system related noises and offer innovative and efficient solutions to control the fuel behavior and soften the slosh impact.
- Low permeability: thanks to advanced composite structures and functional component integration allowed by plastics, combined with efficient process innovations.
- Crash worthiness: through high impact performance.
- Fire resistance.
- Suitability for hybrid power trains: plastic fuel tank systems are fully compatible with hybrid power trains and only a few minor adjustments on fuel system components are required. Enabling high design freedom and integration feasibility, plastic fuel tank systems require only minor component adjustments to be fully compatible with hybrid powertrains.
- Cost effectiveness achieved through the combination of great design and manufacturing flexibility for complex shapes, mechanical and chemical resistance, and quantity of material to be used. Besides, plastics can be processed at lower temperatures than steel or glass.
Since their introduction for fuel systems manufacturing application, Plastics have widely demonstrated superior performances over their competing technologies.
Member of PlasFuelSys
As a global player in producing automotive plastic parts, Plastic Omnium is a member of Plasfuelsys, an European association of plastic fuel tanks producers and developers. Plasfuelsys is a panel for professionals from all participating fields of knowledge, but this association also informs government and citizens about the benefits of modern plastic fuel tank systems. Plasfuelsys is part of the EUPC (European Plastics Converters) based in Brussels, Belgium.
To reduce permeation levels and meet PZEV, LEVII or Japanese regulations, multilayer fuel systems tanks have been developed. The manufacturing process is called multi-layer extrusion or coextrusion "COEX". This process is especially used for the production of tank shells with barrier layers limiting hydrocarbon vapor emissions into the atmosphere.
Coextrusion thus allows us to meet the increasingly strict requirements set up by environmental standards in terms of hydrocarbon emissions.
Coextrusion consists in extruding a parison made up of several different materials layers with complementary properties. Each material is fed by a separate extruder and the layers are formed in the head.
Each layer of material has a specific purpose:
- Outer virgin HDPE allows components welding, ensures protection against UV and can have conductive properties when used for blow-molded filler pipes.
- Regrind is made of excess material generated by the manufacturing process.
- Outer and inner adhesives ensure the cohesion of the structure and the regrind/EVOH compatibility.
- EVOH barrier ensures permeation performance.
- Inner virgin HDPE provides mechanical resistance and can have conductive properties when used for blow-molded filler pipes.
An EVOH (Ethylene-Vinyl alcohol) layer is introduced between HDPE layers, with adhesive to ensure the material’s integrity. EVOH is the material which creates a barrier against hydrocarbon emissions. EVOH does not adhere to Polyethylene: an intermediate layer is thus necessary to avoid the delamination of one layer with the other layers: this is the adhesive layer.
With environmental regulations, like PZEV, applying to an increasing number of vehicles on the North American market and rising end-user demand for non-polluting vehicles, the race is on to design and manufacture environmentally cost effective solutions.
Currently, vehicles sold in the United States must meet «Tier II/LEV II» evaporative emission standards regarding hydrocarbon (HC). Tier II/LEV II standards, limiting evaporative emissions to 0.5g/day, are the most stringent evaporative controls in the world.
Facing a high level of pollution, California Air Resources Board (CARB) adopted even stronger environmental policies to promote ZERO Emission Vehicles (ZEV). Under ZEV, carmakers are obligated to sell some advanced technology vehicles with significantly fewer pollutants.
Some of these advanced technology vehicles include PZEV (Partial Zero Emission Vehicles). PZEV vehicles nearly match the low environmental impact of an electric vehicle with an advanced internal combustion engine and fuel system. The fuel system evaporative emissions of PZEV vehicles is limited to 0.054g/day, barely 10% of the vehicle limit for TierII / LEVII.
This PZEV regulation is applied only to a portion of vehicles sold in California and a few US states, thus limiting the PZEV production volume. The challenge is then to have a solution adapted to these small volumes.
AUTO INERGY, with its PZEV process, offers to OEMs a way to upgrade conventional blow-molded fuel systems to PZEV fuel systems with very few changes in the production line.
Since 2006, AUTO INERGY has already equipped more than 340,000 PZEV vehicles in the United States.
Several innovating add-ons were developed to reduce the permeation of various components or areas of the fuel systems:
INFILM, a multi-layer coex film laser welded over fuel system components, reducing permeation path,
INPINCH, a low permeation pinch detail formed during blow molding, reducing pinch emissions by 4.
TSBM stands for Twin Sheet Blow-Molding. This patented process from Plastic Omnium combines the components integration possibilities of half-shell processes with the advantages of standard blow-molding process.
With this new process, Plastic Omnium is able to reach new performance levels with regards to:
- Permeation: inserting components inside the fuel tank allows reducing the number openings in the tank shell hence reducing permeation path opportunities.
- Useable volume: TSBM allows more freedom in the positioning of valves in most adequate location to reach higher useable capacity for a given space in the vehicle.
- Further integration possibilities: TSBM allows for the integration of larger components, thus being suitable for hybrid applications (TSBM offers an easy way to integrate internal reinforcements in all locations, or slosh noise devices like INBAFFLE).
While traditional plastic tank blow molding process requires multiple welding operations of externally mounted components, TSBM integrates components into the fuel tank during the blow molding process.
TSBM technology increases the system design flexibility and allows the integration of standard or specific components, in order to get optimized fuel functions, such as:
- Large capacity components for enhanced fuel pump feeding.
- Complex shape components for dynamic mechanical resistance and noise reduction.
- Enhanced venting function with ideal components location in the tank.
- Wide materials range available thanks to a unique component fixation technology patented by Plastic Omnium.
- Combined functions for limited number of components, for cost and weight optimization.
In production since 2008 and awarded by several automotive and industrial organizations, TSBM meets the strictest emissions requirements while providing performance, weight and costs benefits.
During the polyethylene sheets extrusion, a central core is placed between the mold halves in order to fix, by welding or rivet snapping, the accessories required by the fuel functions. Components that can be attached to the central core include baffles, gauges, valves, jet pumps, lines, fuel modules, and canisters.
Whatever the hybridisation level, we have a plastic fuel system answer!
Vehicle electrification is an automotive trend confirmed by the arrival on the market of powertrains with varying degrees of hybridisation. Plastic Omnium, through its Auto Inergy division, assists OEMs in the development of solutions fitted to each hybrid configuration.
1 - Micro-hybrid / mild-hybrid vehicles
This first form of vehicle hybridization is spreading rapidly, particularly through the introduction of 'Stop & Start' vehicles.
On vehicles equipped with this technology, "slosh noise" due to fuel movements in the tank when the vehicle stops is no longer masked by engine noise and therefore slosh noise reduction becomes necessary.
Plastic Omnium has developed a family of different "in tank" noise reduction solutions called INBAFFLE, improving acoustic performance of hybrid vehicle fuel systems. This is based on an unprecedented acoustic approach: right from the early stages of the design of the fuel system, Plastic Omnium uses computer simulation techniques to take into account vehicle requirements and predict and improve vehicle acoustic performance.
2 - Full-hybrid vehicles
On these vehicles, the electric motor has sufficient power to drive the vehicle on its own during a limited period of time. Plastic Omnium already equips or will soon equip more than 20 vehicle models of this type and supports the introduction on the market of these new hybrid motorizations allowing "all electric" drive for short distances.
3 - Plug-In Hybrid Electric Vehicles (PHEV)
Future plug-in hybrid vehicles, whose more powerful batteries can be recharged by connection to the power supply, should bring a new dimension as they will be able to drive in all electric mode for much longer distances.
Plastic Omnium develops appropriate fuel storage solutions for this new level of hybridization with a technology for gasoline versions, where fuel vapours can not be purged in the normal way by the engine when in all electric mode or when the vehicle is stopped.
To meet this new requirement, Plastic Omnium offers sealed plastic fuel systems with the capability to store hydrocarbon vapours until the gasoline engine is running and able to purge and treat them.
Plastic fuel systems for hybrid vehicles offer a significant weight saving of approximately 40% compared to similar steel solutions for Full-Hybrid and PHEV, while providing the same level of safety that has made the plastic fuel system successful.
Blow-molded plastic pipe is a light weight cost effective solution for automotive fuel filling application.
This technology provides large flexibility in design to address any particular vehicle configuration. Filler pipes can be blow-molded in 2 or 3 dimensions, with constant or variable diameter, with or without degassing and recirculation...
It can accommodate most ways to fix the pipe to the tank: welding, using a rubber hose, fitting with a metal ring, or using of a quick-connector. Similarly, filler head can be welded or crimped. Blow molding allows for larger head for better filling performances.
It is fully compatible with capless systems. Plastic Omnium, through its Auto Inergy division, developed and commercialized its own capless system: CLINFILL.
Pioneering advanced technologies, Plastic Omnium has developed a high productivity, low cost process to produce 3D filler pipes.
- Plastic raw material is molten and flows through the extrusion head of the blow molding machine to form the parison.
- The parison is taken by a robot gripper and laid down into a shaping mask during the blowing cycle of the previous part without any loss of time.
- Upon mold opening, the finished part is extracted from the top cavity and the shaping mask drops the parison into the lower cavity.
- Both ends of the filler pipe are automatically removed by in-mold cutters achieving high part accuracy while reducing costly secondary operations.
- Mold closes again and blowing cycle restarts.
This 3D process is combined with Plastic Omnium’s post cooling process for optimal geometrical reproducibility. The filler pipe is processed further in the finishing line.
In addition to increasing productivity, Plastic Omnium’s 3D filler pipe blow-molding optimizes investment thanks to the process and machine flexibility which can operate in single or twin station mode.
Today, Plastic Omnium is already using this process for several programs.
Why use plastics for Filler Pipes?
As for Fuel Systems, the use of plastics for filler pipes has several advantages
- + Weight reduction contributing to the reduction of CO2 emissions.
- + High flexibility addressing the most complex shapes.
- + Optimal safety guaranteed through excellent shock resistance.
- + Corrosion free properties for extended product life.
- + Compliance with the most stringent local and global environmental worldwide standards thanks to technologies diversity.
INBAFFLE, efficient slosh noise reduction devices
Plastic Omnium offers a wide range of innovative and efficient solutions that control fuel behavior, soften slosh impact and reduce the noise generated by fuel systems, to comply with the more stringent noise requirements of hybrid vehicles and increase passengers' comfort.
Noise reduction is a key challenge in modern automotive design: acoustical treatments can increase vehicle weight up to 200 kg. Acoustical requirements extend to low & mid range vehicles as well.
As noise levels from the more obvious sources are reduced, more subtle noises are unmasked, even more noticeable on hybrid vehicles when operating in electric mode: not only aerodynamics and road noises but also fuel related noise, especially the noise caused by the fuel waves’ motion inside of the tank. Plastic Omnium has developed a complete slosh noise reduction approach for the diagnosis and quantification of slosh noise sources.
This approach is essential for future performance improvements and has led to the development of the INBAFFLE family of noise reduction solutions that soften the slosh impact, introduce fuel damping.
With this new products range including natural and inserted baffle, Plastic Omnium anticipates acoustic constraints linked to hybrid vehicles.
All INBAFFLE solutions are customizable to OEM’s requirements and specifications: Plastic Omnium baffles are adapted on a case by case basis depending on the design and application of each fuel system.
Plastic Omnium slosh noise solutions can be integrated:
- on assembly line (spring loaded or clipped baffles).
- or during the blow-molding process (patented innovation).
With INBAFFLE, Plastic Omnium offers a family of technical solutions to solve slosh noise problems.