This 'mechanical' control is backed up by electronic stability control, which boosts performance and safety margins, in line with the Alfa Romeo philosophy. The four-wheel drive car is the state of the art in technical terms and offers important advantages.

• Q4 permanent four-wheel drive with a Torsen C self-locking differential makes for better roadholding, entertainment and smooth responses. Other technological archetypes with electronically controlled joints do not achieve the optimal balance between understeer and oversteer or the smoothness that are innate in the Alfa 159, and translate into superb active safety.

• The torque split in favour of the rear axle makes driving even more entertaining, because it makes the car even easier to handle, without detracting in any way from stability during sudden lane changes on the motorway, or other emergency manoeuvres.

• The possibility of travelling safely when grip is poor without having to use electronics to split torque, enhancing the enjoyment of driving.
  
  We could say that the Alfa 159 Sportwagon Q4 interprets four-wheel drive from the Alfa Romeo point of view: it is basically a 'mechanical' system enhanced by cutting edge electronic technology to guarantee maximum comfort and entertainment, combined with superb performance and absolute safety.

Sophisticated technology for total control

The Alfa 159 Sportwagon adopts the most sophisticated electronic systems to control the car's dynamic behaviour, and to raise the dynamic limits even higher, so that they increase safety but are not intrusive for the driver. The intervention of these devices was studied in simulations and exhausting track tests to ensure that the car is always entertaining to drive. The lavish safety equipment is described below.


ABS complete with EBD

The Alfa 159 Sportwagon features an excellent braking system backed up by the BOSCH 5.7 ABS anti-lock braking device, one of the most advanced on the market. It has four active sensors and a hydraulic control unit with 12 solenoids. The ABS system incorporates Electronic Brake force Distribution (EBD), which distributes the braking effort to the four wheels so that it prevents them from locking, maintaining full control of the car in all conditions. The system also adapts to the grip conditions of the wheels themselves and the efficiency of the brake pads, thus preventing the latter from overheating.


VDC (Vehicle Dynamic Control)

VDC is Alfa Romeo's interpretation of ESP (Electronic Stability Program), the system that intervenes when conditions are close to the limit and the car's stability is at risk, to help the driver to control the car. VDC is a sporty device, as you would expect of an Alfa on which roadholding is excellent, and lets the driver enjoy total control of the vehicle as long as conditions are normal, only cutting in just before the situation becomes critical. The VDC system is always engaged.

On the other hand, MSR (Motor Schleppmoment Regelung) cuts in if the driver changes down suddenly in poor grip conditions, giving torque back to the engine to prevent skidding due to wheel lock. To do this, VDC constantly monitors tyre grip on the road, both longitudinally and laterally, and if it detects a tendency to skid, the system intervenes to recover direction and stability. Sensors measure the rotation of the car around its vertical axis (yaw speed), the lateral acceleration and the steering lock set by the driver (which indicates his chosen direction). It compares these data with the parameters elaborated by an electronic control unit and uses a complex mathematical model to establish whether the car is taking a corner within the grip limits, or if it is about to skid at the front or the rear (understeer or oversteer).

To recover the correct trajectory, the system generates a yaw contrary to the one that is causing the instability, braking the relevant wheel (inside or outside) individually and reducing the engine power (by adjusting the throttle valve). This is the peculiar feature of the device developed by the Alfa Romeo engineers. The brake adjustments are modulated so that they are as smooth as possible (and will not disturb the driver) and the reduction in engine power is also limited, to guarantee excellent performance at all times and superbly enjoyable driving.

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