Acceleration sensor

ECU Steering sensor

Acceleration sensorDisplacement sensor

CES damper

CES damper

inputOutput

Suspension Solutions Engineered to Customer Needs

Tenneco’s Continuously Controlled Electronic

Suspension (CES) is another example of our

responsiveness to customer needs. CES pro-

vides superior vehicle handling without com-

promising ride comfort by using our extensive

knowledge of ride control products and com-

bining our resources with the electro-mecha-

nical expertise of Öhlins Racing. The result is

an innovative system that gives customers an

additional opportunity to differentiate their

vehicles and achieve a stamp of individuality

in an increasingly competitive market.

No Compromises!

The Continuously Controlled Electronic Suspension System eli-

minates the need to compromise between high levels of vehicle

passenger comfort and the safety afforded by maximum vehicle

grip on the road and sureness of handling.

Conventional vehicle suspensions are passive, and specify a

pre-set level of shock absorber damping. Softer damping pro-

vides comfort, but at the cost of sub-optimal road holding and

handling. At the other end of the range, firmer damping gives

the driver better control and stronger vehicle grip on the road.

However, the sports car “feel” means passengers experience a

rougher ride.

Tenneco’s CES is a semi active suspension system that overrides

the trade-offs between comfort and handling. It continuously

adjusts damping levels according to road conditions and vehicle

dynamics, such as speed, turning and cornering. CES delivers

comfort without sacrificing the safety of sure handling.

With CES there are no compromises!

The Technical Side

CES incorporates continuously variable electro-mechanical

valves, developed by Öhlins Racing. These advanced compo-

nents replace conventional piston and base valves. The unique

CES design delivers a ratio of 1/20 between the minimum and

maximum damping force levels at lower velocity ranges up to

o.2 m/s. At higher velocities above 1m/s the ratio is reduced

to 1.5. Moreover, the slope of the low velocity bleed curve is

variable.

These characteristics are extremely important to the overall ride

quality of the vehicle. In addition, the large range between mini-

mum and maximum damping force curves ensures that a CES-

equipped vehicle always has the damping force levels necessary

to control the vehicle’s dynamics.

CES valve adjustments occur very rapidly to produce diffe-

rent damping forces. Typically, adjustments take place within

10 milliseconds. This adjustment speed provides effective

control of wheel resonant vibrations up to 20 Hz. As a result,

wheel hop frequency control is achieved in addition to body

frequency control.

How CES Works

A powerful Electronic Control Unit (ECU) lies at the heart of the

CES System to exploit the full potential of the electro-mechanical

valving system. The ECU – which can be based on a 16-bit or

32-bit micro controller – processes data sent by a group of sen-

sors placed at key locations on the vehicle. The sensors include

three acceleration sensors mounted on the vehicle body and

four displacement sensors. These devices feed data to the ECU

regarding steering wheel angle, vehicle speed, brake pressure

and other chassis control information.

The ECU utilizes control software that processes the sensor

information in real time and sends signals that independently

adjust the damping level of each shock absorber valve. CES

dampers allow a large separation between maximum and mini-

mum damping levels and adjust instantaneously to assure the

optimum in ride comfort and firm, safe vehicle control.

Future enhancements of the control software will recognize

individual driving styles by recording driver actions and create

an appropriate control strategy.

What it all Means

Technical specifications aside, CES achieves the continuous

adjustment of damping levels according to road and driving con-

ditions. It switches instantaneously from levels that are as soft

as possible to provide maximum comfort to levels that are firm

enough to provide optimal road holding and handling.

CES Applications

Tenneco's CES shockabsorbers are used in production on: the

Volvo S60R, V70R, S60, V70 and S80 (including new S80, model

2007), the Ford S-Max and Galaxy. Furthermore on the Audi A6

and A6 Avant the CES System is combined with air suspension.

Tenneco's CES shockabsorbers are also in development on a

number of other manufacturer's vehicles.

Leaflet_CES_GB_3.indd 2-3 20-03-2008 11:10:26

Continuously Controlled Electronic Suspension

Tenneco’s CES Delivers Exclusive Benefits

• Improved primary ride motions through independent control of the vehicle body movements – heave, pitch and roll

• Reduced wheel hop due to demand-specific damping and wheel-frequency control

• Improved safety and security due to better road- holding capabilities on rough, uneven road surfaces as tyre force variation is reduced

• Enhanced handling through control of load transfer characteristics of the suspension during transient movements

• Reduction of high-frequency road disturbances transferred through the dampers

• Improved secondary ride characteristics such as rolling plushness, impact harshness and shake reduction when driving conditions allow very soft damping levels

• Improved comfort due to demand-specific damping and variable low-velocity bleed slope

• Opportunity for vehicle manufacturers to further improve vehicle stability control systems through integration with the CES damping system

I.Z.A Schurhovenveld 14203800 Sint-TruidenBelgiumPhone: +32 (0) 11 703 474Fax: +32 (0) 11 703 646www.eu.tenneco-automotive.com

Please do not hesitate to contact us if you require further information.

Leaflet_CES_GB_3.indd 4-5 20-03-2008 11:10:43