As the European Commission drafts some welcome proposals to force carmakers to design vehicles less likely to injure pedestrians in the event of an accident, Matthew Beecham reports on Autoliv ‘s progress in developing a device to create a ‘softer landing’ for victims. He also looks at the efforts BMW will go to to put their ‘signature’ on headlamps as well as yet more gizmo-stuffed seat technology to help cops keep an eye on robbers in the US.



Pedestrian friendly cars are just round the corner


In Europe alone, more than 7,000 pedestrians are killed when struck by cars every year. The EU Commission is therefore considering mandating pedestrian protection for all new vehicles. Head injuries account for the vast majority of the fatalities.


At the international vehicle safety conference ESV (Enhanced Safety of Vehicles) held earlier this month in Amsterdam, Autoliv researchers presented their new system to protect passengers when struck by cars. Autoliv’s ‘pedestrian protection system’ uses sensors in the front bumper of the car to send signals to two actuators which lift the rear part of the bonnet (or hood). This gives the bonnet a sufficient deformation range to ease the impact of the pedestrian’s head and reduce the risk of contact with hard engine and car structure parts close underneath.
















Without pedestrian protection.


Figure 1

With pedestrian protection.


Figure 2

While pedestrians are injured by cars in many ways, Autoliv has concentrated its efforts on the most life-threatening injuries: those to the head. According to Yngve Håland, Autoliv’s Research Director, collision protection systems for pedestrians have been studied since the mid-1980s. Very few proposed solutions, however, are either effective or economical, he says. “Our solution has the advantage, not to require any changes of the car design that could for instance increase fuel consumption.”


Although the idea of lifting the bonnet is not new, to make it happen in time before the head hits the bonnet has proved a tough job. Developing a sensor that can distinguish between a human leg and, for instance, a lamp post has been even more difficult.


What is new, however, is Autoliv’s patented solution. The world’s number one airbag supplier has transferred some its know-how in passive safety systems to come up with a novel concept. Compressed steel bellows, empty until a pedestrian is struck, then inflate by gas generators. Two bellows – one on each side of the bonnet – are inflated to lift the bonnet about 10 cm. This is done in 60-70 milliseconds after the bumper has hit the pedestrian’s leg. A typical head-to-bonnet impact at 40 km/h occurs at about 150 milliseconds after the leg is first hit. By then, Autoliv’s device has already raised the bonnet to its injury reducing position.


Following lab test, Autoliv claims its system significantly reduced the critical injury value HIC (Head Injury Criterion) to levels consistently below the proposed EU standard.


Of all car-pedestrian accidents 95% per cent occur at under 60 km/h impact speed. The average impact speed is about 40 km/h. The proposed EU directives are based on this impact speed.










Autoliv’s head impact test results using proposed European test.


Figure 3

Is it a BMW?


As the use of clear plastic lens on headlamps gathers momentum, the consumer’s eye is naturally drawn to the high-tech wizardry now on display. So carmakers are now working more closely than ever with their lighting suppliers to find ways in which differentiate their cars from the pack.


In developing various solutions, Hella recently introduced light guide technology in series production for the BMW 5-Series. The special feature of the luxury car’s headlamps is the position or parking light in light guide technology. Fed by the light of a 10-watt bulb, light guide strips are wrapped around each of the round headlamp modules, making the typical four-eyes-look of a BMW unmistakable both during the day and at night. For the rear combination lamps, instead of the twin lights with two 5-watt bulbs used previously, four horizontally arranged plastic light guides strips spruce up the appearance. A total of eight LEDs feed the red light guides from both sides and emits it in the right places. They look good in the day, too. Vertically arranged cylinder lenses interact with fine horizontal lines on the plastic patterned lens to produce a brilliant effect on the high-gloss vapourised reflector by breaking the light coming from the outside.













BMW 5-Series front lamps.

BMW 5-Series rear combination lamp.



Figure 4

Figure 5

Looking ahead, Hella expect to offer long signal lamps, flat contour lighting and contour lighting which continues around the tail end using micro-optics. They also expect this technology to soon feature in main and auxiliary headlamps, too. According to Dr Burkard Woerdenweber, director of Hella’s research and test centre, so-called signature lighting as used in the BMW could become very popular amongst other carmakers over the next few years. “Using our light guide technology, we can put any signature on any car. It won’t be long before this technology will permeate down the car segments.”


Riding shotgun


Last time round, we took a look at the latest gizmo-stuffed seats that may appeal to the young and young at heart. But there are some special all-singing, all-dancing seat gadgets on offer for the US police, too. As part of its ‘Intertronics’ product range, Lear is marketing a seat-mounted audio and video recording module. Perched on the seat above the driver’s shoulder, Lear’s CruiseCam features a range of cameras, microphones, control panel and recording equipment ‘designed to meet the specialised requirements of law enforcement personnel’. By mounting the camera to the seat frame rather than clipping it to the visor, cops can keep an eye and ear open on villains sitting in the back as well as capture road incidents as they occur. Gotcha!










CruiseCam


Figure 6