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Transmission system

One million units

One million units of the AS Tronic, an automatic transmission system from ZF for heavy commercial vehicles, have come off the production line. Over the years, the system developed from manual shifting to automatic shifting via CAN.

The AS Tronic (Photo: ZF)

THE GERMAN COMPANY'S AUTOMATIC TRANSMISSION SYSTEM for heavy commercial vehicles has achieved a landmark figure over the past few days. One million units of their automatic transmission have come off the production line since production got underway in 1997at the location in Friedrichshafen. The AS Tronic is available in various configurations for commercial vehicle variants, for example delivery traffic or long-distance traffic, coach, construction equipment or rail vehicle.

"For almost two decades, commercial vehicle manufacturers around the globe have been relying on ZF's AS Tronic transmission range when it comes to automatic gear shifting," explained Fredrik Staedtler, head of
ZF's Commercial Vehicle Technology division. "It is considered a milestone in drive development and has meanwhile become indispensable in modern-day commercial transport."
ZF developed the first fully automated commercial vehicle transmission with the AS Tronic in 1997. Apart from the then development partner Iveco (Italy), today numerous other international truck manufacturers use the automatic transmission system. However, the low-wear system is also used in coaches, construction equipment, and in rail vehicles.

From manual gear change to automatic change with CAN

While the driver had to preselect gears manually on the early semiautomatic AS Tronic transmission, the second generation of the transmission launched in 2000 relieved the driver of the need to change gear: automatic gear selection and electronically controlled gear changes reduce the strain on the driveline, thus increasing the service life of the driveline components. By networking transmission electronics and engine management via the CAN network, the gearshift strategy used by the AS Tronic ensures the engine operates in the optimum speed range. In this way, the power is transmitted efficiently – thereby saving fuel – to the drive axles.

The AS Tronic (Photo: ZF)

The automatic commercial vehicle transmission performs valuable work in the giants on the streets, whether in long-distance heavy goods transport, delivery traffic, or special vehicles. With 12 or 16 gears, the engine operates in an economical range. Communication between engine, clutch, and transmission preserves the entire driveline – both when maneuvering at crawling speed and on the road.
The integrated retarder enables fading-free deceleration, preserves the brakes, and increases safety. The company says, the AS Tronic control unit ensures coordinated clutch work and shifting, so the driver can concentrate on traffic. Besides the automatic mode, the manual mode is available on request.

Extension of the transmission range

There is an entire transmission range available, covering a torque range between 500 Nm and 3100 Nm. The AS Tronic lite (500 Nm to 1100 Nm) and the AS Tronic mid (800 Nm to 1600 Nm) are mainly used in light delivery trucks, buses, and medium-duty commercial vehicles, while the larger members of this transmission family are suitable for heavy trucks and construction vehicles. With its twelve speeds, the transmission system covers the torque range from 1600 Nm to 3100 Nm while the sixteen-speed version offers a fine spread of gear ratios for engines with up to 2600 Nm.

The entire series can be combined with the Intarder, the company’s transmission brake. This can be integrated into the transmission. Inside the transmission, the Intarder not only boosts the engine braking power, but also reduces the workload of the service brake by up to 90 % – particularly on long downhill stretches. All of this enhances safety as well as reduces the impact on the environment and lowering maintenance costs.

Successor ready and waiting

Coinciding with the production milestone of the AS Tronic, ZF is starting a new chapter in the history of this transmission type: Traxon, an automatic transmission system, which will be produced at the location in Friedrichshafen and will replace the AS Tronic over the next few years.

The basic transmission is suitable for torque requirements of up to 3500 Nm and can be linked to five modules. The system features an anticipatory shifting strategy courtesy of Prevision GPS. It gives truck manufacturers the opportunity to link up the transmission with GPS data and digital map material. In this way, unnecessary gearshifts can be avoided – for example when a conventional transmission control unit shifts up a gear before an uphill gradient or a narrow bend, just to shift down to a lower gear shortly after.

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