Audi plans to equip most of its large models with continuously variable transmissions after the launch of the Audi A6 Multitronic later this year.
The A6 Multitronic is the first large-engined car to be coupled with this type of transmission in Europe.
Previously, CVTs were mated almost exclusively to small engines with a displacement of two liters or less. The A6 comes with a standard 2.8-liter V-6 that generates 200 hp.
The Multitronic can handle much greater torque thanks to a new type of chain with wider links. The chain will be produced by clutch supplier LuK Inc. of Langen, Germany.
The roots of the CVT can be traced to Dutch company Van Doorne Transmissie BV. In the late 1970s, the company invented a metal belt that linked two pulleys. Hydraulic pressure makes each pulley wider or narrower, causing the belt to ride higher or lower in the pulley and changing the gear ratio.
20 YEARS OF WORK
Until now, manufacturers have used the Van Doorne type of push-belt system, which is effective for engines up to about 2.0 liters in capacity.
The new Multitronic transmission is the result of 20 years' development. It has both a fully automatic mode and a sequential manual mode with six forward gears.
Audi decided to introduce the Multitronic system after market research showed demand for more efficient automatic transmissions.
'In France and Italy, customers wanted a transmission that offered better acceleration than conventional automatics,' said Claus Korger, the A6's brand manager. 'In other countries, including Germany, the need for improved fuel efficiency became apparent.'
Half of all Audi A6s currently are equipped with conventional automatic transmissions. Audi says the Multitronic is marginally quicker and more fuel-efficient than the manually shifted A6.
In the long term, Audi wants to equip all larger models with Multitronic, including the A4 and A8 ranges, diesels and Quattro models.
100,000 A YEAR
'More development may be required for application with V-8 and turbo engines,' said Audi spokeswoman Judith Nitsch. 'There may be a technical limit for the system.'
LuK spokeswoman Christa Siefert said the company has invested $52 million in production facilities. Annual production capacity eventually will rise to 100,000 units, she said.
Audi says it will charge customers $47 more for a Multitronic than a conventional automatic transmission. The A6's automatic transmission typically costs about $2,100 more than a manual version.
'The Multitronic's price may even go down ... when production numbers start to increase,' Korger said.
Multitronic offers continuously variable ratios in automatic mode, but has six fixed ratios for quick manual shifting in Tiptronic mode. The transmission weighs 15 pounds less than the conventional Audi automatic box because of its lightweight magnesium casting.