With a variant of its popular EcoLife that has been tailored to coaches, ZF is pursuing even more market share as it promotes the benefits of a clutchless, powershift gearbox in a wide variety of applications
ZF has signalled a more aggressive approach to the coach market with the formal unveiling of a variant of its six-speed EcoLife automatic gearbox specifically tailored to the sector.
It complements existing EcoLife variants that are already popular. They remain part of ZF’s line-up. However, the newcomer has a number of improvements to suit its application.
It is already available in the Irizar integral range and the Neoplan Tourliner; Irizar UK in particular has delivered a number of EcoLife Coach-equipped i6, i6s and i8 integrals. Van Hool and VDL will follow suit soo.
Principal among the upgrades made by ZF is an ability to accept up to 2,300Nm of input torque. That makes the EcoLife Coach compatible with engines in the 460bhp bracket, and while ZF has not yet outright confirmed it, that figure looks likely to grow further to 2,500Nm.
But while the initially single-model EcoLife Coach gearbox can take 2,300Nm of torque, it does not have to. It works just as well with lower-rated engines.
MAN provided a Tourliner with the D26 rated at 2,100Nm for demonstration last week, and ZF wants to work with more OEMs to incorporate the EcoLife Coach into their vehicles. It does not rule out further coach-specific versions with lower input torque maximums, too.
The benefits
The EcoLife Coach has a number of internal modifications. The lockup clutch has been strengthened and changes have been made to the torsional damper, while software has been customised to coach use.
Another upgrade is to the cooling system. As a result, the primary retarder can be used for as long as necessary on downgrades. ZF has performed extensive trials in Israel and Spain, and it reports no concerns about overheating.
That dovetails with an increased auxiliary braking tolerance. The retarder delivers up to 1,900Nm of stopping torque, and in gears 3-6 a further 900Nm of engine braking can be handled concurrently for a total braking torque capability of 2,800Nm.
ZF also promises exceptional durability. Its existing EcoLife range in urban bus applications come with a B10 life – an expected point by which no more than 10% of units will have failed – of 700,000km. The EcoLife Coach extends that to one million km, with oil change intervals of up to 240,000km. Other than that, it is maintenance-free.
Compare and contrast
ZF’s other gearbox aimed at coaches is the AS-Tronic automated manual transmission (AMT). It will be superseded by the TraXon in 2018, but the manufacturer is keen to stress that EcoLife Coach does not replace either AMT.
“EcoLife Coach is the optimal choice where average speeds are below 45km/h, where the coach spends time in urban areas, or where it deals with difficult topography,” says Dr Jochen Witzig, who is responsible for ZF’s development of coach and bus gearboxes.
“At lower road speeds the EcoLife delivers better economy than an AMT. The engine does not need to work at higher revs to deliver torque, which is where fuel consumption is highest.”
Dr Witzig presented a pair of shell graphs to back that up. Based on real-world urban driving, they demonstrate that the EcoLife does indeed keep engine speeds lower at times of peak torque demand.
In applications where the coach spends most of its time cruising, ZF says that an AMT will continue to deliver the best fuel economy. However, to that comparison must be factored in periodic clutch replacement.
“There are no limitations to using EcoLife Coach on a motorway all day, but at average speeds above 45km/h the fuel economy argument favours an AMT,” says Senior Manager Commercial Vehicle Technology Bernd Wachter.
Put to the test
routeone has driven both the Tourliner mentioned above and a Cityliner with the EcoLife Coach gearbox coupled to the D26 engine at its 460bhp/2,300Nm rating. Both display the characteristics that have come to be expected from the EcoLife. Drivers notice no difference between the new variant and those that have been in the market for some time, and the input torque is handled impeccably.
On a hilly route in the Allgäu region, the combination of a powerful engine and a fully-automatic gearbox proved its worth. Progress under such circumstances is made much more rapidly than with an AMT.
The EcoLife Coach is a sound product. ZF expects to introduce it to more vehicle OEMs during 2018 and it is particularly focusing on those vertically-integrated manufacturers that have thus far favoured their own units.
routeone comment
Compelling arguments for fully-automatic gearboxes in coaches are many. They remove the potential for component abuse by less-able drivers, they make dealing with urban traffic and difficult topography much easier, and they are extremely robust.
With the EcoLife Coach, ZF is addressing the market’s slow but sure move towards engines that produce ever more torque. High-torque, low-speed engines deliver excellent efficiency. It is incumbent on the gearbox maker to keep up with that – hence its suggestion that a 2,500Nm version will follow. The EcoLife can already take 2,700Nm in rail applications.
ZF’s advice that fully-automatic gearboxes do not suit all applications bears repeating. They don’t, and its forthcoming TraXon promises to up the game for AMTs. But in urban traffic or testing terrain, experience last week shows that automatics are as unbeatable as ever.
