Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sensor skin of DuPont™ Hytrel® contributes to pedestrian safety

09.04.2008
Magna Electronics Europe chose DuPont™ Hytrel® 5556 thermoplastic polyester elastomer for the outer skin of a sensor strip designed to reduce the risk of pedestrian injury from a frontal collision with a car.

The sensor strip is made in sandwich construction. Developed by systems supplier Magna Electronics Europe, part of the MAGNA Group, this new sensor forms a vital part of the so-called active bonnet. The company chose this high-performance type of Hytrel® for its effective combination of properties, including good aging resistance and very good elastic behaviour at temperatures from 85 °C to –40 °C.


Photo: DuPont
Made by Magna Electronics Europe, a sensor strip helps to reduce the risk of pedestrian injuries resulting from a frontal collision with a car. The strip, between 1,1 and 1,4 metres long, is made in sandwich construction. For the strip’s outer skin Magna chose DuPont™ Hytrel® 5556 thermoplastic polyester elastomer.

The sensor strip, between 1,1 and 1,4 metres long, depending on the model, is located between front bumper and radiator. During its whole working life it is exposed to water from road and rain, road salt solutions, dust and wide temperature variations. “Due its nearness to the radiator and as a result of solar radiation it may have to work at up to 85 °C; in winter it may be at –40 °C,” says Ralf Konnerth, Component Manager at Magna Electronics Europe. “We looked for a material that would ensure the sensor’s reliable operation at all times and under all conditions. Hytrel® met these demanding requirements. This plastic has good aging resistance, is robust, and keeps its elasticity even at low temperatures, which is vital for the sensor’s operation.”

Due to the part’s length, the two strips of Hytrel® forming the outer skin are produced by means of cascade injection moulding. Compliance with very close production tolerances is a substantial prerequisite for the sensor’s reliable operation. DuPont gave Magna Electronics Europe substantial technical support. “DuPont’s technical experts helped us with their own tests to determine the optimum injection moulding parameters and tool design,” adds Konnerth. “We also received valuable guidance how to assemble the sensor’s ‘inner life’—an optic fibre which is embedded in polyurethane foam—which is adhered onto the two halves of the outer skin.” The plastics surfaces are given a pre-treatment to improve the adhesion of the PU foam to the Hytrel®.

Magna Electronics Europe’s pedestrian protection sensor is currently installed in the Jaguar XK and Citroën C6. These two upmarket models are the first to offer ‘active bonnet’ technology. Other models will follow.

Background information: How the ‘active bonnet’ works
The sensor-operated ‘active bonnet’, one of the latest developments in automotive design, is intended to improve pedestrian safety. Inside the sensor strip, which is installed between the front bumper and the radiator, is a soft polyurethane (PU) foam in which an optic fibre made of polymethylmethacrylate (PMMA) is embedded. A light-emitting diode (LED) launches light impulses to the optic fibre. The LED is synchronised with a receiver at the other end of the sensor strip. The receiver registers the amount of light that actually arrives and constantly compares it with the amount of light emitted. If an object impacts the sensor strip, attenuation in the optic fibre increases and the amount of light received becomes less than the amount emitted. From the difference between the two, electronic measuring equipment connected to the sensor calculates the force of the impact. From the progression of the force over time the electronics can draw a conclusion as to the nature of the impacting object. It does this on the basis of an algorithm developed in the course of many tests. If it concludes that the object was a person, it ignites pyrotechnic actuators which within about 40 ms lift the bonnet a few centimetres. This increases the distance of the impacting body from the hard motor components, thus absorbing more energy. It also changes the angle in such a way that a pedestrian will not strike the windscreen with his head. This device is effective at speeds up to about 45 km/h.

Magna Electronics Europe, a wholly-owned subsidiary of MAGNA International, is the MAGNA Group’s centre of competence for vehicle safety and for the development of complete vehicle modules. It develops simulates and tests modular and functional systems in one of the most modern development and testing centres in the world. In the last ten years this source of innovation has created a reputation for itself as a reliable and flexible development partner for all major European automotive companies, especially in the domain of passive vehicle safety.

The DuPont Engineering Polymers business manufactures and sells Crastin® PBT and Rynite® PET thermoplastic polyester resins, Delrin® acetal resins, Hytrel® thermoplastic polyester elastomers, DuPont™ ETPV engineering thermoplastic vulcanizates, Minlon® mineral reinforced nylon resins, Thermx® PCT polycyclohexylene dimethyl terephthalate, Tynex® filaments, Vespel® parts and shapes, Zenite® LCP liquid crystal polymers, Zytel® nylon resins and Zytel® HTN high-performance polyamides. These products serve global markets in the aerospace, appliance, automotive, consumer, electrical, electronic, healthcare, industrial, sporting goods and many other diversified industries.

DuPont is a science-based products and services company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 70 countries, DuPont offers a wide range of innovative products and services for markets including agriculture and food; building and construction; communications; and transportation.

The DuPont Oval Logo, DuPont™, The miracles of science™ and all product names denoted with ® are registered trademarks or trademarks of DuPont or its affiliates.

Horst Ulrich Reimer | Du Pont
Further information:
http://www.dupont.com

More articles from Automotive Engineering:

nachricht Improvement of the operating range and increasing of the reliability of integrated circuits
09.11.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

nachricht New algorithm for optimized stability of planar-rod objects
11.08.2016 | Institute of Science and Technology Austria

All articles from Automotive Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>