New Suspension Component Credited for Improved Performance at Lower Cost
Fiat adopts an integrated jounce bumper system on its Punto model that integrates several components into one to deliver better performance and a lower system cost.
The component is the result of an integrated design, materials and processing approach by a team from DuPont, Fiat, Insit, and Ossberger. Together they developed a novel approach that improves driving dynamics and passenger comfort, essential in Fiat vehicles. The part will be featured at the K-show, 16th to 23rd October in Düsseldorf, at the DuPont exhibit in Hall 06, C43.
Part of a vehicle's shock-absorber system, the jounce bumper is designed to absorb impact and dampen noise, vibration and harshness (NVH) by preventing the metal shock absorber spring from fully compacting during shock impacts due to potholes, curb and objects in the road. It also offers an additional spring function to improve vehicle behavior when negotiating smaller holes on the road surface and cobblestones or during quick direction changes or sudden braking.
The featured jounce bumper is part of a vehicle's shock-absorber system designed to absorb impact and dampen noise, vibration and harshness (NVH).
In orange, the suspension using a jounce bumper of foam polyurethane (PUR) and in black, the thermoplastic solution made of DuPont™ Hytrel® thermoplastic elastomer integrating four functions.
Using thermoplastic instead of foam polyurethane (PUR) or rubber derivatives delivers high elastic recovery; excellent fatigue and durability; and low stiffness variation over a wide range of temperatures. The design eliminates the need for metal or reinforced polyamide saturation cups and acetal or rubber rings normally used to increase energy absorption and can integrates dust protection.
"Materials are critical in component design and the best results happen when the three primary phases in product development – design, materials and processing - converge," said Patrick Cazuc, Automotive Director Europe, DuPont Performance Polymers.
DuPont modified Hytrel® to deliver better mechanical performance, particularly under high strain conditions, excellent shape recovery, a good balance between stiffness and low-temperature properties, thermal stability resulting in low molding variation and excellent processing capabilities. It also takes advantage of a blow-molding process that uses an Ossberger machine, which can tightly control the thickness profile, facilitating optimum energy-absorbing properties with a maximum compression ratio.
DuPont uses non-linear Finite Element Analysis (FEA) and Expert System software to develop designs that can be tailored to an OEM's specific force displacement curve requirements. This software is able to model plastic deformation, large deformation, nonlinear material behavior and processing limitations to create the optimum thickness profile.
Rapid prototyping of mold tools and laboratory testing is available at the DuPont European Technical Centre. CERAM, an independent French automotive dynamic analysis road center, can provide vehicle road tests to help optimize the jounce bumper performance.
The jounce bumper has been tested by several professional test drivers. Some of whom have reported a higher comfort and steering feedback with a reduction of the front axis roll angle. In addition, several OEMs have also tested the new design on a variety of vehicles over tens of thousands of kilometres without any behavioural issues. The tests have proven that the new design delivers similar performance to PUR, but with lower part damage. Indeed, after traversing 3,000km of cobble stoned roads the Jounce Bumper made of Hytrel® exhibited less than 3% permanent deformation far below the industry target of 10%.
DuPont offers more than 100 materials and product families for the global automotive industry. Through its global application development network, DuPont Automotive is committed to collaborating with customers throughout the value chain to develop new products, materials, components and systems that help reduce dependence on fossil fuels and protect people and the environment. For more information, visit automotive.dupont.com.
Contact: Carole Davies
DuPont Performance Polymers is committed to working with customers throughout the world to develop new products, components and systems that help reduce dependence on fossil fuels and protect people and the environment. With more than 40 manufacturing, development and research centers throughout the world, DuPont Performance Polymers uses the industry's broadest portfolio of plastics, elastomers, renewably sourced polymers, filaments and high-performance parts and shapes to deliver cost-effective solutions to customers in aerospace, automotive, consumer, electrical, electronic, industrial, sporting goods and other diversified industries.
DuPont (NYSE: DD) has been bringing world-class science and engineering to the global marketplace in the form of innovative products, materials, and services since 1802. The company believes that by collaborating with customers, governments, NGOs, and thought leaders we can help find solutions to such global challenges as providing enough healthy food for people everywhere, decreasing dependence on fossil fuels, and protecting life and the environment. For additional information about DuPont and its commitment to inclusive innovation, please visit www.dupont.com.