“ESP on board!”: safety come as standard
 

In line with the strategy of recent months, all versions of the Fiat Grande Punto MY 2008 are fitted as standard with ESP (Electronic Stability Program) to ensure maximum control of the car’s dynamic behaviour. This important choice is much more than a marketing opportunity, coming instead under the heading of social commitment and responsible driving. Apart from anything else, Fiat Automobiles has always been first to come up with ambitious initiatives that aim to raise public awareness - and particularly the awareness of young people - of the strategic importance that safety, accident-prevention and road safety education must hold in any progressive society today.

With the aim of supporting the knowledge of state-of-the-art safety devices and providing incentives for their adoption as a measure for preventing or reducing accidents, the Fiat Grande Punto MY 2008 supports the slogan “ESP on board!” as part of the campaign “Choose ESC!” launched by the European E-safety aware! Platform, an initiative sponsored by the European Commission.

In detail, the sophisticated ESP on the Grande Punto MY 2008 cuts in under extreme conditions when car stability is at risk and also helps the driver to control the car. To achieve this result, the ESP continually monitors tyre grip in both longitudinal and lateral directions. If the car skids, it cuts in to restore directionality and ride stability. It uses sensors to detect rotation of the car about its vertical axis (yaw speed), car lateral acceleration and the steering wheel angle set by the driver (which indicates the chosen direction). It then goes on to compare these data with parameters generated by a computer and establishes – via a complex mathematical model – whether the car is cornering within its grip limits or if the front or rear is about to skid (understeer or oversteer). To restore the correct trajectory, it then generates a yawing movement in the opposite direction to the movement that gave rise to the instability by braking the appropriate wheel (interior or exterior) individually and reducing engine power (via the throttle). And herein lies the specific aspect of the device produced for the Fiat Grande Punto MY 2008. It acts in a modulated fashion on the brakes to ensure the action is as smooth as possible (and the drive is not therefore disturbed). The engine power reduction is contained to ensure outstanding performance and great driving satisfaction at all times. The ESP is permanently engaged.
 

One specific feature of the ESP fitted to the Fiat Grande Punto MY 2008 is the incorporation of a Hill Holder system that assist the driver on hill starts. It operates when the ESP control unit perceives a change in vehicle gradient by means of a longitudinal acceleration sensor. During hill starts, the control unit is ready to intervene when first gear is engaged and both brake and clutch pedals are pressed. Front calliper pressure is thus maintained for about 1.5 seconds after the brake pedal is released so that the driver can set off with ease. The Hill Holder function does not operate when setting off downhill with the first speed engaged. The system performs in the same way with reverse engaged: during downhill starts, the system is active but deactivated during hill starts. Lastly, a HBA hydraulic braking assistant automatically increases brake circuit pressure during emergency braking.

The ESP System on the Fiat Grande Punto MY 2008 also includes an ASR (Anti Slip Regulation) system that optimises traction at any speed with the aid of the brakes and engine control. The device computes degree of slip on the basis of wheel rpm calculated by the ABS sensors and activates two different control systems to restore grip. When an excessive power demand causes both drive wheels to slip (e.g. in the case of aquaplaning or when accelerating over an unsurfaced, snowy or icy road), it reduces engine torque by reducing the throttle opening angle and thus air flow.

If only one wheel slips (e.g. the inside wheel following acceleration or dynamic load changes), this is automatically braked without the driver touching the brake pedal. The resulting effect is similar to that of a self-locking differential. This allows the Grande Punto MY 2008 to get out of trouble easily on road surfaces with low grip.

The ASR is activated automatically whenever the engine is started but must be turned off by means of a switch on the central dashboard. The ASR need be turned off only when snow chains are used because the wheel must be able to slip by tiny amounts to pile up the snow so that force can be transmitted to the ground and the ASR tend to prevent this occurring.

Last but not least, the MSR (Motor Schleppmoment Regelung) system, an integral part of the ASR, cuts in during sudden gear changes, while shifting down, to restore torque to the engine and thus prevent excessive driving of the drive wheels that could lead to a loss of vehicle stability, particularly under conditions of low grip.