What is a front-end module?  It depends who makes it and for whom.  Front-end modules typically encompass the bumper, headlights, radiator and various others parts. Matthew Beecham reviews some notable trends and developments in this arena.

The major functions of the front-end components are to act as a body frame, taking in and cooling air, protecting the vehicle and its occupants in the event of a collision, properly illuminating the front of the vehicle as well as improved appearance and exterior styling.

The most important potential benefit of modular construction is standardisation, allowing suppliers to offer standard solutions to different manufacturers and hence bring costs down.  More specifically, by shifting programme management responsibilities to the supply base allows the automaker to decrease their interfaces with different suppliers.

Front-end modules have been sourced by European automakers for some time. Although this market is showing some signs of maturing, the North America, Chinese, Korean and even Japanese automakers are now taking a keen interest in outsourcing these modules.

By outsourcing front-end modules, automakers are able to reduce the number of operations on their assembly lines, simplify their supply chains, reduce modular weight and improve the ergonomic aspects of the assembly process.  It can also help cut tooling costs and improve working capital. The most important potential benefit of modular construction is standardisation, allowing suppliers to offer standard solutions to different manufacturers and hence bring costs down.

For the supplier, the added responsibility for design and development brings new opportunities. While front-end module suppliers take on a larger responsibility than just supplying individual parts, that responsibility brings with it a greater chance to increase sales.

There are three main markets for front-end modules: Europe, North America and South Korea.  In addition, there is some manufacturing in Japan and China. Until recently, the European market was seen as the mainstream for front-end modules with a number of manufacturers.  Yet lately this market has shown some signs of stabilisation to the point where it is reaching maturity. While the European market stabilises, the North American market for front-end modules continues to grow.  

Not only is the front-end important aesthetically and functionally, it also plays a fundamental role in safety, says Faurecia.  During low-speed collisions, it must protect the expensive components in the front of the vehicle, thereby reducing repair costs.  During collisions at higher speeds, its absorption capacities become secondary, says Faurecia, but it plays an important role in terms of establishing compatibility between different vehicle brands and models to compensate for differences in height and direct energies towards zones of structure deformation of the car.  Above all, it has taken on a whole new dimension following adopted standards of pedestrian protection. 

Protecting the pedestrian

Indeed, interest in front-end modules has increased partly due to the focus on vehicle safety issues and the need to comply with guidelines from the European Union for pedestrian safety.  The first phase of the EU’s stringent pedestrian protection rules took effect in October 2005.  This first phase considers ‘leg’ and ‘adult head’ impact and measures injury criteria.  In response, some automakers have added plastic energy absorbers to their vehicle’s front bumpers. The second phase will progressively come into force starting in 2010.  This will introduce criteria concerning ‘upper leg’ (hip impact) and ‘child head’ impact and will see more stringent ‘leg’ impact criteria.

Continental has developed a so-called Intelligent Pedestrian Protection System. Stephan Zecha, advanced engineering, passive safety and ADAS business unit of Continental´s chassis and safety division, told us how it works.  He said:  “Intelligent Pedestrian Protection starts considerably before a collision with a pedestrian by applying preventive measures in order to avoid or mitigate the collision with the pedestrian. This preventive concept has two major advantages:

“First, a certain amount of collisions can be totally avoided when preventive protection measures can be introduced in a timely manner.

“Second, even if complete collision avoidance cannot be achieved, the reduction of the collision velocity will reduce the injury risk for the primary contact of the pedestrian with the vehicle significantly. Even more important is the influence on the secondary impact. The secondary impact is the impact of the pedestrian on the street after the primary contact with the vehicle. This leads to even worse injuries than the primary contact. Such unfortunate effects of the secondary impact can only be reduced by reduction of the collision velocity. This however can only be achieved with preventive protection measures.

“Thus the pedestrian protection system envisaged by Continental will use ADAS [advanced driver assistance system] sensor(s) for the recognition and tracking of the pedestrian in critical evolving situations. A straightforward collision risk algorithm will predict the collision risk with the pedestrian(s). Based on the calculated collision risk level and the predicted time to collision there will be a stepwise activation of protection measures starting from warning information for the driver up to autonomous brake maneuvers.  This is a logical extension of the ContiGuard® concept which is Continentals sophisticated approach for preventive vehicle safety.

“The unique feature is the combination of advanced ADAS sensors for the pedestrian recognition with unique algorithms for the collision risk prediction. These algorithms will especially take into account a realistic motion prediction for the pedestrian.”

In explaining what is in the pipeline from Continental with respect to pedestrian protection, Dr Christian Kuhrt, director, development and platform, passive safety, passive safety and ADAS business unit, also from Continental´s chassis and safety division, said:  “A very promising concept for preventive pedestrian protection is the application of a stereo camera for the detection, classification and tracking of pedestrians. This sensor concept can then be combined with the announced measures for driver warning or autonomous brake maneuvers.

“An even more straightforward concept for preventive pedestrian protection is the application of cooperative transponder systems. This system consists of detection units in the vehicles and miniature transponders which are carried from the pedestrians. This system allows the detection and chronological tracking of pedestrians by using the detection units with very high reliability. Even pedestrians which are hidden by other objects can be detected and tracked with such a system. Continental investigates this promising technology in the frame of a major German research initiative Ko-FAS.

“For contact-based active hood systems, Continental develops and supplies sensing systems including reliable and robust impact detection algorithms using either accelerometers or pressure sensors mounted in the bumper structure.”

For its part, Valeo claims that its so-called Safe4U reduces the severity of pedestrian injury by 20 – 40%.  Valeo states its Safe4U has an active pedestrian detection system using a radar placed above the upper crosspiece and two cameras, one on each side of the bumper, which can distinguish pedestrians from other hazards.  Once it has identified the risk of collision, two actuators release the upper crosspiece from its supports in a split second. Valeo says that this allows the upper part of the front-end to swing back, limiting the maximum effort and spreading it over a longer distance.  The system is reversible: if the impact does not take place, the actuators move back into position and reconstitute the front-end.

Material matters

A number of material innovations in the bumper area have emerged recently. For example, Renault is using ExxonMobil Chemical’s Exxtral TPO (thermoplastic olefin) for the front and rear bumpers of the Renault Laguna Coupe.  Renault says Exxtral TPO meets its specifications for excellent fit and finish, along with good impact strength and a balance of stiffness and toughness that is required for automotive bumpers.  Volkswagen has used a similar grade for the bumpers on its new VW Golf and Renault has used these materials on the 2006 Espace and 2007 Laguna.

Meanwhile, US-based Milliken Chemical has developed a reinforcing agent for polyolefins that reduces part weight by as much as 15% versus mineral-filled systems and is said to deliver a good balance of stiffness and impact strength. Milliken says that its so-called HPR-803 is capable of replacing glass-reinforced PP or expanding automotive applications for PP beyond the current hidden structural automotive applications to include highly visible components like bumpers and door panels.

On the recycling front, Mazda Motor says is has developed a system which enhances the process it uses to recycle used bumpers into raw plastic resin for use in new vehicle bumpers. It said the new technology is the first to enable recycling of used bumpers from different manufacturers at the same time. The automaker has recycled bumpers since the early 1990s, initially turning them into underbody trays. The latest recycling technology can recycle all types and makes of bumper, removing the need for separate collection systems for each automaker’s products.

Matthew ‘Beechy’ Beecham