German component manufacturer pulls curtain back on innovations

At a news conference held this summer near its corporate headquarters on the German shore of Lake Constance, ZF Friedrichshafen AG previewed innovations that it will display at this month's huge IAA commercial-vehicle show in Frankfurt am Main, Germany.

The company supplies truck, bus, car and specialty-vehicle OEMs around the world with manual and automated transmissions, axles, chassis components and steering systems.

American fleet managers are perhaps most familiar with the firm through the joint venture - ZF Meritor - it has with ArvinMeritor.

In the U.S., that operation markets FreedomLine automated transmissions, which are sold by ZF in Europe under thecompany's AS Tronic trade name.

Hot Stuff The chief items discussed at the briefing included the rollout of new AS Tronic automated transmissions for European light- and medium-duty commercial vehicles; an independent front-axle suspension concept being developed for trucks; and a look at the future of steer-by-wire systems in commercial vehicles.

Wolfgang Vogel, executive vp of the commercial vehicle division, reported that the AS Tronic family of automated mechanical transmissions is growing, with models being introduced both for Europe's light-commercial and construction truck markets.

He noted that the ZF Meritor joint venture in the U.S. is currently limited to FreedomLine units designed for Class 6-8 vehicles only.

Vogel described the AS Tronic as the only product in its range that uses fully integrated "two-pedal" technology - meaning no clutch - available in both direct and overdrive versions.

He pointed out that the AS Tronic entered the on/off-road sector this year with units that are being supplied to such European OEMs as Iveco and MAN.

According to Vogel, automated transmissions are making inroads into Europe's market for light-duty (under 6.5 tons) commercial trucks much as they are stateside.

"They offer several advantages over manual transmissions," he stated. "They bring clutch life up above 700,000 km (434,000 mi.); protect against mishandling (driver abuse); lower fuel consumption; and provide driving convenience."

In general, he said automated units perform better than the "average driver" ever can. And the upshot? "The AS Tronic provides lower lifecycle costs."

Vogel predicted that by 2007, automatic units will account for 50-70% of the market for light-duty commercial truck transmissions in Western Europe.

Short Throws ZF also markets manual truck transmissions and Vogel noted improvements being made to those products. These include adoption of passenger-car-like "short throw" shifting and further development of the ZF Intarder, a retarder integrated into the gearbox.

Updating the axle and suspension arena was Reinhard Buhl, group vp of off-road driveline technology and C.V. axle systems.

"OEMs want axle systems and suspension and chassis technology that uses a systems approach while reducing weight, improving safety and operator comfort, and helping preserve road surfaces," he stated.

Buhl said the systems approach could lead to ZF providing integrated axle-air suspension units to OEMs. (For more on that topic, see feature story on pg. 61.)

He said ZF's new ADM (automatic driveline management) system for all-wheel-drive vehicles teams a mechanical transmission and a pneumatic unit with a microprocessor to automatically engage or disengage the differentials in the axles and transfer case.

According to Buhl, use of the ADM system will reduce tire and transmission wear while improving vehicle safety. Some typical ADM applications he listed include on/off-road vehicles such as those used in fire & rescue, snowplowing and various modes of construction.

X-Shape ZF is working on a radically new chassis suspension design it expects to offer on Class 8-type European trucks by 2002. Buhl said it uses an "X-shaped" four-point link that integrates the functions formerly carried out by V-links and stabilizers.

"The four-point link offers a better ride, less weight, higher ground clearance and the ability to do 'quick-change' repairs," Buhl explained. "It also reduces the number of components needed by up to 80%." He noted that a lighter version could also be developed for medium-duty trucks.

Buhl also discussed ZF's concept for an independent front suspension, which it expects will bring "coach comfort" to medium- and heavy-duty trucks while also helping to dampen pavement wear - apparently a big theme in Europe these days.

"Using an independent front suspension," said Buhl, "would reduce unsprung mass, which would both improve ride and reduce road damage. It would also allow lower step-in heights for vehicle operators, a smaller turning circle, and possibly reduce weight."

Steer by wire Dr. Peter Kilgenstein, vp of ZF Lenksysteme, a joint venture between ZF and Robert Bosch GmbH, discussed the prospects for steer-by-wire systems in trucks.

While R&D work has been ongoing for some time at the joint venture, Kilgenstein said for steer-by-wire systems to succeed in the marketplace, the safety "block" of customers will have to be overcome. "The road," he observed," is very narrow compared to how long it is."

Kilgenstein pointed out that ZF Lenksysteme has already begun producing a steer-by-wire system for rear axles, dubbed the Servocom RAS-EC (rear axle steering, electrically controlled). But he also noted that the continuation of development work hinges on the fact German law does not permit steer-by-wire systems on front axles.

However, according to Kilgenstein, RAS-EC offers several advantages, including better maneuverability, a tighter turning circle, less tire wear and improved dynamic stability.

No one at ZF - or elsewhere - knows which of these component developments will next make it across the pond to benefit fleets in North America. On the other hand, everyone knows the world grows smaller with every passing day.