Active performance chassis with Four-C Technology
Three chassis settings: Comfort, Sport and Advanced Sport
Shock absorber settings updated every other millisecond
Electronically-controlled AWD for fast respons
Brembo brakes with four-piston aluminium calliper
Safety on the highest level
The new Volvo S60 R and V70 R are equipped with what is probably the world’s most advanced active performance chassis, with Four-C Technology (Continuously Controlled Chassis Concept).
The promise of the noted Volvo PCC and PCC2 concept cars has now been fulfilled by the Volvo S60 R and V70 R.
No other cars can combine the uncompromising road contact of the extreme sports cars with the comfort essential in a family car, in the same way as Volvo’s R cars do.
Performance on demand
Three control buttons in the middle of the instrument panel are the only clue to the chassis setting options available via the driver’s index finger:
In the "Sport" setting, the chassis is optimised for ordinary driving, but above all on winding roads and at high speeds. In this setting, the R-chassis will offer the driver a well-balanced mix of driving pleasure, body control and travelling comfort.
Pressing the "Comfort" button increases the softness of the chassis and insulates the body from irregularities in the road. This is the ideal setting for urban traffic and the family holiday, but above all for slippery surfaces, where a "softer" car is easier to drive and more compliant.
In the "Sport" and "Comfort" settings, the R-chassis uses the control technology called Sky Hook which makes the body float along over irregularities in the road.
"It’s almost as if the body of the car is suspended from above on virtual shock absorbers. Hence the expression Sky Hook", explains Marcus Rothoff, head of Four-C Technology development at Volvo Car Corporation.
Sports car characteristics
When the driver presses the "Advanced Sport" button, the Volvo S60 R or V70 R is transformed into a pure sports car. The chassis is optimised for maximum roadholding in all situations, especially when driving on winding roads and at high speeds. In fact, it can even be used for track driving.
The DSTC (Dynamic Stability and Traction Control) system can allow a higher degree of skid before the system cuts in and brakes the wheels, straightening up the car. This is obtained by pressing the "DSTC" button once. In this mode, the spin-control is also turned off.
DSTC can also be disabled by pressing the "DSTC" button five times in succession. This ensures that the DSTC function is not disabled by mistake.
These driver options, which alter the character of the car towards comfort or performance, are made possible by the active performance chassis with Four-C Technology.
What makes Four-C different from other chassis concepts is its ability to process enormous amounts of information from different sources in the car.
Sensors to measure the longitudinal, lateral and vertical acceleration of the car relative to the road are located at various points on the chassis.
There are also sensors to measure:
the rotation speed and vertical movement of each wheel
steering wheel deflection and velocity
cornering (yaw rate)
engine torque (calculated)
braking interventions by ABS and DSTC
All these sensors send signals to the microprocessor in Four-C, which computes the motions of the car and adapts the hardness of the shock absorbers so that the car is always parallel to the road surface.
Updating 500 times a second
The shock absorbers are updated with new information 500 times a second. In practice this means that the shock absorbers in the Four-C chassis are constantly adjusted when the car is being driven.
This is made possible by a totally new technology, the first in the world of cars, developed jointly with Öhlins Racing AB, one of the world’s leading developers of high-tech shock absorber systems, and shock absorber manufacturer Monroe.
The computerised electrical system of the Volvo S60 R and V70 R, known as Multiplex, also sends information to the Four-C system. On severe braking, for instance, the Four-C system receive the braking information a few milliseconds before the brake pads touch the brake disc. By then, the Four-C microprocessor has computed by how much the braking will cause the front end of the car to dip, and uses this information to set the shock absorbers to maximise control and tyre grip.
When the car is accelerating, Four-C receives the corresponding information from the longitudinal acceleration sensor. Similarly, the system passes on information about a sharp deflection of the steering wheel a few milliseconds before the car actually changes direction.
So Four-C can predict what is going to happen, making the pun in its name (foresee) highly appropriate.
Electronically-controlled AWD system
The Volvo S60 R and V70 R have an electronically controlled AWD system which is basically the same as in the Volvo XC90 and S60 AWD, for instance.
But on the R models, the four wheel drive is not there for better off road driveability. Instead, it is optimised for performance, roadholding and stability.
The AWD system is also connected to the Multiplex system of the car. This means that the AWD system can interact in a unique way with DSTC, which in turn means that the car can deliver precisely the driving characteristics the driver wants.
The short cut-in and cut-out times of the AWD system, less than 100 milliseconds, allow the driver to compensate for and control oversteer and understeer extremely quickly.
When parking, the AWD system is controlled to prevent the front and rear axles working against each other in tight turns, making the Volvo S60 R and V70 R easy to manoeuvre.
On braking, the system is deactivated so that the brake system in ABS mode can operate without interference, to ensure high stability and a short braking distance.
In the same way the AWD system is deactivated by the DSTC stability control when the DSTC applies the brakes to prevent a skid.
Brakes to match performance
Quick, precise steering response is vital for high-performance cars like the Volvo S60 R and V70 R. That’s why they are fitted with power-assisted steering gear which is controlled by the speed of the car. It is programmed to give maximum servo assistance during parking manoeuvres and then gradually increase the forces in the steering when the speed increases. At top speed the least servo assistance is provided.
Volvo S60 R and V70 R have brakes to match the overall performance of the car. The Brembo aluminium brake callipers have four pistons. Aluminium callipers contribute to rapid heat dissipation and reduce unsprung weight. Lower unsprung weight means better tyre contact with the road.
The ventilated brake discs are all of 330 mm in diameter. The front discs are 32 mm thick and the rear ones 28 mm.
This gives the R-model cars a 100 – 0 km/h braking distance of 37 metres (preliminary figure)
The passive safety in the Volvo S60 R and V70 R is on the same high level as in other Volvo cars. Among other things this means:
Crash-tested in the most advanced crash testing laboratory in the world
Extremely strong safety cage around the passengers
WHIPS, Whiplash Protection System, in the front seats
Inflatable Curtain (IC) for side impact protection
ISOFIX child safety system
Safety belt tensioners at all seats
Side impact airbags for the front seats