Numerous recent studies credit ESP® with being the hitherto most successful active automobile safety system. This accolade recognises it’s ability to give greater vehicle stability under skid conditions, addressing a problem which according to the results of a study by the German insurance industry, causes 25 percent of all accidents involving personal injury and 60 percent of all fatal accidents. Furthermore, a Daimler-Chrysler study based on data from the Federal Office of Statistics shows that after ESP® was fitted as standard, the proportion of Mercedes-Benz cars involved in serious single car accidents fell by around 42 percent. Similar studies by such bodies as the American government's "National Highway Traffic Safety Administration" (NHTSA) and Toyota confirm or better these findings. It therefore stands to reason that in Australia, the Victorian Vehicle Safety Strategy includes the key objective of increasing the proportion of vehicles on the road equipped with high quality active crash avoidance features, such as ABS and ESP.

Greater safety and extra convenience features

Since the start of series production Bosch has continually expanded the potential of ESP®, developing the system further into a scalable range of products with built-in flexibility, which now allow the integration of further safety and convenience features. Such safety functions as "Electronic Brake Prefill" and "Brake Disc Wiping" feature in the Bosch ESP® plus version, enabling shorter braking distances which further increase driving safety. If the driver suddenly lifts his foot from the gas pedal, the "Electronic Brake Prefill" function immediately brings the brake pads into contact with the discs, thus making for more rapid braking in an emergency situation. "Brake Disc Wiping" increases the efficiency of braking when it is raining heavily. Unbeknown to the driver, the brake pads are briefly brought into contact with the brake discs at set intervals, preventing a film of moisture from forming on the discs.

ESP® premium for greater driving dynamics and agility

The most highly developed version of the scalable product range - known as ESP® premium - is based on a conventional hydraulic braking system, but it can perform all the relevant additional functions of an electro-mechanical braking system without making elaborate and costly changes to the vehicle's electrical system. By utilising a much more powerful pump, which now has six instead of the previous two pistons, ESP® premium is able to respond very quickly, with the driver barely hearing or sensing anything at all. It boasts a 90 percent reduction in pressure pulsation compared with the previous ESP models. The rapid pressure build-up is adjusted to the driving situation and because of the lower noise output, more dynamic interventions are possible to assist the driver, without the system being acoustically intrusive. In critical situations the speed of pressure accumulation for autonomous, stabilising interventions is increased by a factor of more than 3. Both the agility of the vehicle and its handling can be improved with this new braking control system. In addition to the high convenience level in terms of noise and pedal feel, the combination of ESP® premium and "Adaptive Cruise Control" (ACC) allows for significant added functionality. For example, the active brake control in combination with additional sensors can expand ACC to ACC "Stop & Go". Using the data from short range sensors, the function automatically applies the brakes in tailgate situations, bringing the vehicle to a complete halt if necessary. When distance permits, the function can start the vehicle moving forward again without the driver having to do a thing. In future, the more dynamic pressure accumulation mentioned above will also allow the development of an automatic emergency brake. ESP® premium thus marks the current state of development in hydraulic braking systems according to the criterion of safety, dynamics, convenience and agility. In addition, it opens up new opportunities for future extensions.

New networking potential: Vehicle Dynamics Management & CAPS

The clear direction for further development lies in the linking of ESP® with other active systems in the vehicle to create Vehicle Dynamics Management (VDM). A network consisting of ESP®, active steering, active chassis and drive train will be created to improve driving dynamics. Further gains in safety for all road users can be achieved through the networking of the ESP® active safety system with passive safety and driver assistance systems. At Bosch, all the activities in this field are brought together in the CAPS (Combined Active and Passive Safety) project. The potential for success lies in making use of synergies which arise when ESP® is combined with vehicle surround sensor systems and passive safety systems. The scalable ESP® range of products offers compatible interfaces for this. Decisive for the future is the perfect interplay of powerful and efficient systems within a networked architecture. The challenges here exist in reducing the complexity of the networks on the one hand, while on the other further raising the already high standard of reliability and availability. The solution lies in standardised basic software, including standard interfaces for systems to communicate with each other. On this basis, vehicle manufacturers and their components suppliers can continue to work closely together, developing powerful and effective mecha-tronic solutions.