Scania spells out the future
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by Brian Weatherley.
• By 2000 heavy trucks will have electronically activated brakes, semi-active suspensions, driver safety airbags, ultraviolet headlights and 550hp engines— if predictions from Scania's vice-president, chassis development and production, Kaj Holmelius come true.
In Sweden last week Holmelius spelt out the Swedish truck maker's vision of "The truck of the 2000s" and the technology likely to be found on it. But he stresses: "We don't fancy technology for the sake of technology it must contribute to the efficiency of the vehicle."
Sarnia is already well down the road with its electronic braking system (FIB), developed jointly with Bosch. ELB was first discussed in 1985 and is currently being evaluated in "market acceptance trials" in Germany (CM Engineer's Notebook 9-15 July 1992). "It's almost ready now; we're finding out if the market is ready for it," says Holmelius,
In a normal truck the air-brake valves are activated pneumatically so that on long artics there can be a delay in transmitting the air along the pipe runs before the brakes are applied. With ELB, the air-brake valves are triggered electronically, leading to faster response times and more even braking across the vehicle. "The longer the vehicle the better, we can save a tenth of a second—and in braking that's a long time," reports Holmelius.
ELB ideally needs to be fitted to both tractor and trailer although the existing air-brake pipes are kept as a safety backup. While operator acceptance of ELB is likely to be slow Holmelius says: "Once they realise it's the only way to get the perfect braking system they'll be prepared to buy ELB."
Along with ELB„ Holmelius also sees integrated retarders and disc brakes being used more on trucks: "We'll probably have discs as an option although it will be some time before we see an end to drum brakes." Holinelius also reckons "air suspension still has a lot of development potential although semi-active suspensions will become common in the future." Such systems could consist of dampers with electronically controlled oil-flow rates and electronically controlled anti-roll bars located by hydraulic rams.
When cornering, or on bad roads, the micro-processor-controlled semi-active suspension would automatically adjust itself to give a better ride. "It could also be connected to the braking system to eliminate nose-dive under heavy braking," says Holmelius.
If chassis suspensions continue to improve, cab suspension "could become unnecessary" in the long run, I lohnelitis believes.
Following the recent launch of its aerodynamic Streamline cab option which cuts the standard R cib's air resistance by 10-15%, 1 loimelius predicts that cabs "will almost certainly become more rounded and wedge shaped with a relatively narrow front tapering out to the sides. Such a shape will require an extremely curved windscreen which has been technically difficult to fit—but new sealing methods are solving this problem." Electronically controlled panels could also be used to reduce the tractor/trailer air pp on attics.
Holmelius says that while Scania could "easily put a safety air bag into a truck on the driver's side, we're not ready to offer it. An airbag in the steering wheel requires little development but there the similarities with car systems end."
The risk to truck passengers is different to those in a car. claims Homelius: "Therefore we've been studying knee-height air bags for the passenger side." Airbags could also be used on interior side pillars in the event of a vehicle rollover, but the rapid inflation and deflation creates its own problems, he says. "A lot of development is required here."
Scania has been working on ultraviolet lighting systems which can increase night-time visibility for drivers by up to 130%. Accident rates could be cut, although the final braking distance is still dependent on vehicle speed and the road surface.
The UV light is non-dazzling and picks up fluorescent material—a full description of the Scania UV truck lighting system will appear in a forthcoming Engineer's Notebook.
Scania sees a continuing growth in the demand for more power. "Ratings will increase", says Holinelius, "With 400-425hp for average long-distance trucks and 525-550hp for top-power models."