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Presseinformation

Press Information Page 1/4, 2011-06-07

ZF Friedrichshafen AG

Konzernkommunikation

Corporate Communications

88038 Friedrichshafen

Deutschland Germany

ZF Develops 9-Speed Automatic Transmission for

Passenger Cars

The world's first 9-speed automatic passenger cartransmission

Fuel savings of up to 16 percent Stop-start, hybrid, and all-wheel drive capableAt the International VDI Conference "Transmissions in Vehicles2011", ZF Friedrichshafen AG presents an automatic

transmission with nine speeds for passenger cars with front-

transverse drive. With its two model ranges, it covers a torque

range between 280 and 480 Nm. Thanks to its construction kit

principle, the basic transmission can be supplemented in line

with special requirements. Thus, different starting elements,

hybrid and all-wheel drive applications can also be implemented

cost-efficiently given the restricted installation space conditions.

Savings of up to 16 percent compared to today's standard 6-speed

automatic transmissions in front-transverse installations: The new

9-speed automatic transmission (9HP) owes this fuel efficiency to

its extremely high total spread of 9.84. Nevertheless, extremely

small gear steps can be realized thanks to the nine speeds. This

does not only have a positive effect on driving comfort but, in

addition, the engine always runs in the consumption-optimal speed

range: In the ninth speed, there are only 1,900 revolutions per

minute at 120 km/h instead of 2,600 in case of transmissions

featuring 6 speeds.

Revolutionary transmission concept

ZF realized the high number of speeds of the 9HP with the help of

four individual gearsets and six shifting elements. It was a big

challenge to place these additional components in the

transmission; in principle, the transmission installation space in

front-transverse passenger cars is highly restricted by the vehicle's

width. For this reason, the gearsets have not been allocated on the

9HP's longitudinal axis but were intelligently nested in. This

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concept was supplemented by using hydraulically operated

constant-mesh elements, since these can be integrated without a

major impact on the overall transmission length and still enable

high efficiency. While multidisk shift elements in the open

condition create drag torques, these losses are very low in dog

clutches. This aspect is particularly important with regard to the

multi-speed concept of the 9HP: Thus, enhanced efficiency

generated by small transmission steps is not lost again via drag

losses due to the rather complex design.

Enhanced performance and less fuel consumption

A torque converter is used in the 9HP as the standard starting

element: Particularly customers in the USA and the Asian markets

esteem its smooth starting and maneuvering quality. Here, a multi-

level torsion damper system minimizes hydraulic losses while,

already at low speeds, facilitating quick bridging of the torque

converter lock-up clutch. This is not only beneficiary for fuel

consumption and comfort but also for driving dynamics. For an

even more direct driving experience, ZF has designed all controlcomponents for shorter response and shift times, actually below

the threshold of perception.

Flexible transmission control

Direct multiple gearshifts are also possible with the 9HP and give

the automatic transmission its sporty character. Thus, the

transmission controls can be influenced by the OEM and the end

customer: Shifting points and shifting dynamics are highly variable

- from emphasize given to comfort and optimized fuel consumption

up to extremely sporty. ZF benefits from its expertise in the area of

software development when engineering such highly flexible

transmission controls: ATSYS, the shifting sequence control,

contains all clutch controls, adaptation functions, and transmission

protection functions while ASIS, the driving strategy, ensures that

the optimal gear is selected for each driving situation - unnoticed

by the driver!

With the 9HP, as a result of cost efficiency and installation space

optimization reasons, ZF engineers did not use a fully-integrated

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mechatronics module for all sensors, actuators, and the electronic

control unit (EGS). Instead, ZF develops and produces the EGS

under its own aegis: It is installed separately from the - now

significantly smaller - hydraulic control unit (HSG), namely on the

upper side of the transmission housing. The EGS's computing

performance can be increased by another 30 percent when

needed. Thus, the 9HP is also equipped for even more

comprehensive software functions in the future. The EGS's

hardware layout has been designed in such a way that the different

OEM requirements can be applied without any problems.

Flexible construction kit

So that the new 9-speed automatic transmission can be installed in

as many vehicle applications as possible, it has been prepared as a

'construction kit': e.g. an additional transfer case can be connected

for the all-wheel drive operation. To this end, ZF developed an all-

wheel drive that can be decoupled (AWD Disconnect). It actuates

the rear axle drive only when needed and, thus, saves five percent

fuel compared to the permanent all-wheel drive. The 9-speedautomatic transmission is, by default and without an additional oil

pump, stop-start capable. Since, in the case of restarting, it is only

one friction shift element that needs to be closed, response times

are indeed highly spontaneous. In addition, the 9HP is easy to

hybridize: On the basis of an parallel hybrid architecture, the

torque converter is then replaced by an electric motor. Finally,

thanks to its open software and interface structure as well as the

powerful electronic control unit, it will be possible to integrate the

unit flexibly in different vehicle concepts. This diversity of the 9HP

construction kit makes the transmission especially efficient for

OEMs.

Caption:

Flexible, powerful, and cost-efficient. The 9 HP construction kit is

designed for different starting elements, hybrid drive, a stop-start

function, and all-wheel drive.

Photo: ZF

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Press contact:

Thomas Wenzel, Manager Technical Press, Tel. +49 7541-77 2543,

Fax: +49 7541-77 902543, E-Mail: [email protected]

ZF is a leading worldwide automotive supplier for Driveline and Chassis

Technology with 117 production companies in 26 countries. In 2010, the Group

achieved a sales figure of EUR 12.9 billion with approximately 70,000 employees.

In order to continue to be successful with innovative products, ZF annually

invests about five percent of its sales (2010: EUR 646 million) in research and

development.

For photos and further press information please visit: www.zf.com

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