Early critical reviews are mixed on whether automated manual transmission (AMT) technology has a bright future in Europe.
Lower-than-expected demand means the several suppliers active in the field must offset initial investments with low volumes, keeping per-unit costs high.
Enthusiasts of the technology believe AMTs, which combine the characteristics of manual and automatic transmissions, could replace manual transmissions in many European cars over the next decade.
Within 10 years, we expect the traditional manual clutch and transmission to have disappeared completely BMW technology spokesman Friedbert Holtz says.
But skeptics such as German transmission supplier ZF say conventional manual transmissions will be the primary technology for mass-market European cars for the foreseeable future.
Manual gearboxes will remain mainstream for at least the next 10 years, says Wolf-Ekkehard Krieg, head of marketing and sales at ZF in Saarbrücken. Despite earlier optimistic growth expectations for AMTs, they will remain a niche.
Early AMT versions did not fulfill high expectations, says automotive analyst Peter Smith of consultancy AID.
AMTs have proved to be slow and not very refined in their operation, Smith says. The only quick and smooth-changing AMT is the Volkswagen double-clutch DSG, which is still expensive. But that may be overcome with better economies of scale.
AID estimates AMTs have about 0.9 percent of the European passenger vehicle market, compared with 19.1 percent for automatics and 80 percent for manual transmissions. Thats about 140,000 units annually. The Smart ForTwo microcar and BMW M5 medium-premium sedan are the only two models equipped exclusively with AMTs.
But automakers and suppliers have been busy refining AMTs after the technology was first developed in the late 1990s for Formula One racing, which demands rapid gear changes at optimum engine speeds.
Most European drivers prefer manual to automatic transmissions. Manual transmissions offer better fuel economy and performance and cost significantly less to purchase – about E2,000 less than an automatic and E700 less than an AMT.
Easy to use
Volume automakers see AMTs as a way of offering consumers a car with the characteristics of an automatic transmission at a more affordable price and with the same fuel economy as a manual. Cars with automatics use up to 15 percent more fuel than those with a manual or AMT transmission.
For most automakers, AMTs do not require new capital investments beyond those for existing manual transmissions. Except for VW, automakers source the add-on AMT modules from independent suppliers.
On the downside, AMTs cost more to build than manuals, and gear changes can be slow and rough in cheaper AMT systems.
Over the past six years, the business model that has evolved is a small group of suppliers working with automakers on specific AMT applications. Magneti Marelli, ZF and Siemens VDO Automotive produce the activators and electronic control units for modules that turn manual transmissions into AMTs.
A different approach
Supplier BorgWarner has a somewhat different deal with Volkswagen. BorgWarner developed and produces VWs double-clutch Direct Shift Gearbox transmission. The DSG takes a different approach to AMT – some competitors argue it is actually not an AMT – with a gear set and double-clutch assembly. Each clutch assembly is engaged with a different gear and the driveline is connected to one clutch at a time. Essentially, the clutch in use channels the driving force while the idle clutch is matched with the anticipated next gear – depending on whether the car is accelerating or decelerating.
The gear-change times take about 40 milliseconds.
Among other AMTs, the division is between mass-market cars with systems using electromechanical actuators with gear changes in as little as 300 milliseconds and those with more expensive electrohydraulic shift actuators. Opel and PSA/Peugeot-Citroen say AMT demand is up to 10 percent on some of its models.
BMW, Ferrari and Alfa Romeo offer AMT systems that appeal to sporty drivers who want quick, responsive automated gear changes and the option of making manual changes.
BMW sells about 20 percent of its 3-, 5- and 6-series models with its Sequential Manual Gearbox (SMG), which uses Marellis electrohydraulic modules.
Marellis modules reduce gear-change times to less than 100 milliseconds on the Alfa Romeo and Ferrari AMTs.
BMWs basic SMG offers gear change times of 150 milliseconds. For the M5 and M6, BMW offers the faster SMG-M, developed in-house, which shifts in 65 milliseconds.
But while growing in Europe, AMTs have not yet expanded into the US or Japanese markets. There, volume manufacturers prefer to offer automatics or continuously variable transmissions on small models.
So what is the future for the AMT?
ZF sees growth in commercial vehicles because AMTs are cheaper than automatics and offer better fuel economy.
AMT applications make sense for light commercial vehicles, said Krieg. AMTs are also available for heavy commercial vehicles.
How it works
An automated manual transmission uses the gears and casing of a conventional manual transmission, but adds a module that automates the mechanical clutch and gear-changing process.
The driver can operate an AMT in either of two modes: as an automatic transmission or a clutchless manual transmission.
There are two types of AMT modules: electromechanical and electrohydraulic. Electromechanical modules, usually fitted on volume models, only make gear changes at average speeds – 300 milliseconds to 500 milliseconds.
Normally found on sportier and more expensive cars, electrohydraulic modules permit faster gear changes – about 100 milliseconds.
The modules add significant cost – they include sensors, activators and specific electronic software. But they fit along the side of the transmission casing, so they do not affect the length of the drivetrain.