DuPont Engineering Design Electronic Magazine
EDITORIAL: The quest for sustainable mobility
By Patrick Ferronato
global automotive marketing director
DuPont Engineering Polymers
(*based on the US EPA Fuel Economy website, assuming a vehicle is driven an average of 15,000 miles per year)
In dealing with one of the greatest challenges facing the automotive industry, we are working with many of our customers to achieve more sustainable mobility in response to high fuel costs, regulatory requirements and the need to reduce CO2 emissions. Among the options currently being explored are ways of improving vehicle efficiency by reducing energy loss through friction, the reduction of overall vehicle weight through advanced metal replacement, and the use of new technologies to boost the output of smaller engines. At the same time, automotive manufacturers are introducing more advanced propulsion systems – from hybrids through fuel cells – that can run on various alternative energy sources.
Contributing to energy savings today
This tremendous challenge has caused us to rethink a number of components and systems, especially in the engine, driveline and fuel systems. The stakes for reducing a vehicle’s carbon footprint and improving fuel economy are high. Several studies show a 25 kilogram (55 lb) weight reduction can yield a 1% increase in fuel economy, depending on the vehicle. A 100 kilogram (220 lb) weight reduction can reduce CO2 emissions by 8.5 grams per kilometer (approximately 0.5 oz per mile). High performance DuPont engineering resins make the replacement of metal parts and components possible, contributing to weight reduction, fuel savings and CO2 emission reductions. DuPont™ Zytel® nylon resin, for instance, has long been adopted for GM’s 3800 series V6 engine manifold. By replacing metal and reducing weight, this change has saved over 2.6 million barrels of oil from 1992-2006.
In a life cycle analysis of the use of virgin glass-reinforced nylon, in place of secondary aluminum, for an engine component of the Ford F250 truck, it was found that the benefits attributable to the reduced vehicle weight far offset energy consumption during manufacture. During the ten year lifetime of 100,000 trucks included in the analysis, a 77 billion BTU (British Thermal Unit) net energy saving was achieved and 11 million pounds (5,000 tons) of CO2 emissions were eliminated. The energy savings could create enough electricity to meet the needs of five thousand homes for an entire year. In addition, DuPont™ Zytel® nylon resin has contributed to weight savings in a number of system components. As an example, described in further detail in this issue of Engineering Design, the use of Zytel® as an alternative to aluminum for the lower section of an oil pan module from Daimler, helped cut the weight of that component by nearly 50 percent.
The stakes for reducing energy loss through friction are also high. Studies have shown that approximately 15% of the energy available in gasoline actually gets used to move a vehicle down the road. The remaining 85% of the energy is lost to engine and driveline inefficiencies, accessories and idling. To help the automotive industry improve efficiency and get more power to the wheel, DuPont has created the “Science of Friction” program to put the science of DuPont materials – from DuPont™ Vespel® parts and shapes to DuPont™ Teflon® – to work and reduce friction, especially in driveline systems. For example, Vespel® demonstrates a 30% to 40% reduction in friction when used in fork pads, which are used to engage gear sets in manual transmissions. Similarly, the use of Vespel® in automatic transmissions can improve the torque loss of seal rings by up to 50%. Additionally, automotive manufacturers can increase loads on thrust washers twofold, encouraging further metal replacement for weight and space savings.
Energy savings for the future
Looking to the future, and with a new generation of propulsion systems in mind, DuPont is also leading the development of safer, more efficient energy storage options for a variety of consumer and industrial applications, including electric/hybrid vehicles. Our focus is on creating energy storage options that result in less wasted energy and heat gain due to low resistance, longer device life from less heat and higher performance materials (chemical and thermal stability), higher energy output due to a thinner separator (resulting in more active materials in the same space) and processing cost savings, due to higher temperature stability and less water absorption.
Key DuPont products in development for the energy storage sector include: DuPont Hybrid Membrane Technology for battery separators; engineering polymers such as Zytel® nylon for battery pack housings, sealants and connectors; fluoropolymer resins for capacitors and lithium ion batteries; and DuPont Teijin Films separators for dry capacitors. For instance, DuPont is developing a battery separator for electric/hybrid vehicles which will enable higher operating temperatures in use, more power generation and lower ionic resistance for increased battery output.
In device testing to date, DuPont has seen up to a 40% improvement in the life of the device with properly designed energy storage components, such as super-capacitors. Our Hybrid Membrane Technology has shown significant advantages in high power applications - in devices it will deliver up to 50% more energy at high discharge rates. Meanwhile, our higher temperature materials have enabled the reduction of production times and broadened device application temperature capabilities. The results of this smarter engineering? The potential for increased power density and less wasted energy and heat gain; increased energy supply and the enabling of smaller devices; higher process temperatures, resulting in reduced manufacturing costs and improved device life and effective barriers to address safety issues.
Significant breakthroughs in sustainability honored
Two breakthroughs in automotive sustainability, featuring high performance polymers from DuPont, were recently honored by The Society of Plastics Engineers (SPE) Automotive Division. An oil pan for Daimler’s new 4-cylinder diesel engine (OM651), the first worldwide to consist of a polymer module (made of DuPont™ Zytel® nylon – see next article), took top honors in the powertrain/chassis category (Daimler representatives Dr. Günther B. Zoll (left), specialist supervisor plastic engine components, and Nuri Tiraki, project development engineer for the OM651, are pictured with the module and award). Meanwhile Ford was named finalist in the powertrain/chassis category for an innovative “capless” fuel filler system which uses DuPont™ Zytel® HTN PPA. The new system is compatible with biofuels and supports the compliance of Ford’s vehicles to all California Low Emission Vehicle (LEV II or PZEV) requirements.