Autoliv actively saving lives

Head-impact results at 40 km/h (25 mph) using the proposed European test limit with a standard hood and with an active hood from Autoliv. Click to enlarge

At its press conference at the Frankfurt Motor Show, Autoliv made clear its intent to save, rather than waste, human life, describing itself as "a company that is 100% devoted to saving lives and limiting injuries." The protection of vehicle occupants has improved significantly over the past couple of decades, thanks in part to Autoliv, which holds more than 3000 patents covering a number of vehicular safety innovations that include an inflatable curtain, a new rollover sensor, one-piece-weaving technology for airbags, and a number of seatbelt and inflator technologies.

The fatality statistics that have been reduced due to airbags, new seatbelt features, and anti-whiplash systems have made more clear the dangers of simply being a pedestrian. In EU countries, pedestrians hit by cars make up 20% of all traffic fatalities, with over 7000 pedestrians being killed every year in Europe. In densely populated countries such as the UK, the rate is as high as 30%, according to Autoliv. In Asia, nearly 2700 are killed in Japan alone, which correlates to 30% of all traffic fatalities in that country. Just about 80% of the fatalities occur when the pedestrian's head hits the hood or windshield structure, while most of the remaining occur when the pedestrian is hurled to the street.

Autoliv's active hood is activated on impact at speeds above 20 km/h (12.5 mph) by a sensor that is able to differentiate between geometries (another car vs. a leg), as well as different stiffness (a pole vs. a leg).

The EU Commission has become increasingly concerned by pedestrian-fatality trends. To address its concerns, it established an agreement in July that outlines a series of new tests that will be conducted to make sure that violence to a pedestrian's head does not exceed certain levels when the head, with a speed of 35 km/h (22 mph), hits the car. (The tests correspond to a car moving at 40 km/h (25 mph).)

The EU test levels are 1000 head-injury criteria (HIC) for 2/3 of the hood surface and 2000 HIC for the remaining 1/3. HIC is an internationally accepted acceleration-based measurement for violence against the head. HIC values under 1000 imply that the risk of life-threatening injury is 15% or less. However, the curve rises sharply; at 2000 HIC, the fatality risk is almost 90%.

Autoliv designed a series of patented "ribbons" into its PPAs that distribute the crash force from the head over a wider bag area, so the bag can be kept small and still be very efficient. The PPAs are only 7 L (0.25 ft3) each.

All new vehicle models sold in the EU member countries must meet the new HIC requirements starting in July 2005. For the windshield area, the agreement stipulates that vehicle manufacturers should monitor the HIC values for all new models. The agreement between the Commission and the automotive industry is due to be approved by the European Parliament next month. Similar regulations are being considered in Japan and are due to become effective more or less simultaneously with the European rules.

In June, Autoliv announced that it had developed an active hood, a new system that could significantly reduce the risk of serious and fatal head injuries to pedestrians struck by cars. The patented design consists of sensors in the front bumper of the car that send signals to two actuators that then lift the rear part of the hood. The lifting elements are compressed steel bellows that are empty until a pedestrian is struck, then inflated by gas generators within 60-70 ms. One bellow on each side of the hood raises the rear part of the hood approximately 100 mm (4 in), which allows the pedestrian's head to contact a deformable and flexible surface instead of the car structure and other rigid parts. The new device also prevents a pedestrian from hitting the lower part of the windshield.

The active hood has proven to be very efficient in laboratory tests. The HIC values have been reduced by as much as 90%, and HIC values below 800 have been recorded in tests conducted according to the agreed EU standards.

The new pedestrian protection airbags (PPA) from Autoliv have been shown in laboratory tests to reduce "drastically" the risk of life-threatening injuries. Click to enlarge

To supplement its active hood, Autoliv introduced at Frankfurt its new pedestrian protection airbags (PPA), which are comprised of an airbag at each A-pillar. "As vehicle hoods tend to become shorter with every new model change, the risk for pedestrians hitting the hard structures around the windshield increases," said Yngve Håland, Research Director at Autoliv. "For this reason, we complemented our initial system by integrating PPAs at the windshield pillars."

The same sensor that triggers the active hood also sets off the PPA system. One of the challenges for engineers was to develop a sensor that could differentiate between a human leg and a light pole or minor fender bender so that the system would not be inadvertently activated. One of the ways the system solves this dilemma is that the vehicle must be driven above 20 km/h (12.5 mph) for it to activate because it is about that speed that life-threatening injuries are more likely to occur to pedestrians. On the other hand, most fender benders occur below those speeds.

Besides the savings of human lives, another advantage of the two systems is their potential for further development. "It's possible to make a combined system adaptive, whereby only the active hood is deployed at low speeds," said Håland. "Depending on the car's front-end geometry, the PPAs can then be deployed at higher speeds, when the risk of hitting the windshield area increases significantly."

- Jean L. Broge

Intier flexes SUV seat muscle

With the right rear and front passenger seats folded flat, the Saturn VUE accomodates long items such as skis.

The flexible interior of Saturn's newest product, the VUE SUV, comes courtesy of Intier Automotive, a recently formed unit of automotive-interiors supplier Magna International. The company designed the seats for the front passenger and rear passengers to fold flat for accommodation of larger cargo such as skis and ladders. The front passenger seatback features a durable and scuff-resistant surface.

Even more innovative than the fold-flat front seat is a rear seat with two-position reclining to 29°. Each section of the 70/30-split rear seat can be reclined or folded flat independently, with single-hand operation. Cargo space is 1785 L (63 ft³) with the rear seats folded.

The rear center-passenger position is fitted with a seat-integrated three-point belt. The outboard rear seats feature adjustable head restraints.

Optional leather seats include manual lumbar control and temperature control.

- Patrick Ponticel