Written on 22.10.2014 - Technology
You have these options:

Improved pedestrian protection and noise reduction under the hood with polyurethane

People travelling on foot in traffic apparently live dangerously. According to the European Commission, about one-fifth of all traffic fatalities in Europe involve pedestrians [1]. Apart from passenger protection, auto manufacturers therefore are also taking a closer look at pedestrian safety.

The Volvo Car Corporation is a leader in the field, using a clever combination of Bayer materials to manufacture the hoods of its four cylinder diesel engines. Two special polyurethane systems provide for a soft “landing” in the event of impact with the hood: the resulting engine hood is elastic, acting as a crumple zone to reduce the effects of impact. The automaker also takes other measures to ensure pedestrian protection.

Volvo Car was in search of an all-around material that offers greater safety for pedestrians, dampens engine noise and can be efficiently processed. The Bayer MaterialScience Oldenburg systems house accepted the challenge: in close cooperation with Czech parts manufacturer Promens Zlin and Volvo Car, it developed a material solution specifically for this application based on a combination of new grades of its Baytec and Bayfit polyurethane systems.

The three partners cooperated throughout the entire development process, from selecting the raw materials and formulating the products, all the way to optimising the manufacturing process. In production, the spray elastomer Baytec enters the mould first. It is responsible later on for the desired stability and smooth surface of the parts.

The foam system Bayfit is then added to the same mould. Its job is to effectively dampen engine noise. The sandwich structure of these two materials is elastic and represents a great advancement in pedestrian protection. With it, Volvo Car says it has set new standards in safety, quality and comfort.

The engine hoods are manufactured in two basic versions: while the engines in standard vehicles are equipped with a black hood, the hybrid cars have a silver-coloured version. Production of the silver-coloured parts begins with the application of an in-mould coating. In the same mould, the subsequent processing steps are then carried out as described above.

[1] http://ec.europa.eu/transport/road_safety/users/pedestrians/index_en.htm