Fuel System Components and Aggressive Biofuel Environments

DuPont elastomers used in fuel system components help reduce permeation.

Global biofuel use is expected to double by 2015, according to “Global Biofuels Outlook 2009-2015” issued by Hart Energy Consulting.  With rapid population growth and a finite source of fossil fuels, the call to develop renewably sourced biofuels is clear, but that also places new demands on fuel system components. At the same time, automotive manufacturers are using technologies, including engine downsizing, direct injection, turbocharging and diesel engines, to meet more stringent emissions regulations and improve fuel economy.

But smaller, higher-performance engines, turbocharging, engine encapsulation, aggressive biofuels and more confined engine compartments generate hotter and tougher operating conditions for fuel system components, such as elastomers.

This has led to the development of a new generation of heat-, pressure- and chemical-resistant products within DuPont.

The Impact of Biofuels and Downsized Engines on Fuel System Components

Fuel system components and engine components must resist biofuels, temperature extremes and mechanical stresses for the lifetime of the vehicle. In particular, biofuels can be highly aggressive to the elastomers and plastics used in fuel system and engine hoses, gaskets and o-rings, inlet manifolds, ducts, valves and bushings — causing degradation, loss of sealing force, and eventual failure. Permeation and leakage through such components can be key sources of hydrocarbon emissions.

Ethanol-containing fuels can cause permeation, particularly in hydrocarbon rubbers such as nitrile rubber, thus increasing volatile emissions and fuel loss. Biodiesel can also attack nitrile and other rubber materials widely used in fuel-handling hose, gaskets and seals.

Stability of DuPont™ Zytel® Nylon Resins in Ethanol

Zytel® 612 nylon resins and Zytel® HTN high-performance polyamides have also demonstrated stability in ethanol and ethanol blend fuels and remain stable following immersion in E0, E10, E50 and 100% ethanol at 90°C for up to 2,000 hours, and can therefore be specified for applications requiring long-term service in fuels with ethanol content.

New Renewably Sourced DuPont™ Zytel® RS 1010 Nylon Resin in Biodiesel

DuPont™ Zytel® RS 1010 nylon can be used in diesel and biodiesel fuel lines. Debuting with Fiat, the renewably sourced long-chain nylon was chosen in preference to competitive grades of PA12 on the basis of its superior temperature resistance and long-term aging performance in biodiesel. It captured a “Most Innovative Use of Plastics” award from the Society of Plastics Engineers in the Environmental category.

A Leader in the Development of Renewable Fuel Solutions

As a leader in the development of renewable fuel solutions, DuPont offers specialty products that improve yield and productivity for producers throughout the biofuels value chain.

DuPont is partnering with BP through a joint venture, Butamax Advanced Biofuels, to commercialize biobutanol which has a higher energy density than ethanol, leading to up to 25% higher fuel economy.  Butanol can be blended with gasoline at higher concentrations in existing vehicles; it can also be blended at refineries and transported via existing fuel infrastructures.

In addition, through targeted Pioneer® hybrids, innovative enzymes and FermaSure® fermentation additives, DuPont offers first-generation ethanol plants ways to increase their efficiency in yield as well as uptime, thereby making first-generation biofuels more competitive and more sustainable.

As the industry leader in automotive materials including fuel system components, DuPont will continue to collaborate with automakers, OEMs and energy companies to find innovative, sustainable solutions to face the global challenge of reducing dependence on fossil fuels.