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In late 1996, Daimler-Benz together with WABCO and Scania together with Bosch presented the first electronically controlled brake systems (EBS) in their towing vehicles. Since then roughly 2000 ACTROS per month have been produced with EBS. Other vehicle manufacturers will introduce EBS in the near future [5]. The technical advantages of EBS combined with the increased application of disc brakes, are: improved safety through shortened stopping distance better vehicle stability and brake comfort optimized brake monitoring and higher profitability However, with this first step the technical possibilities are limited to towing vehicles combined with conventionally braked trailers. The overall braking performance of the combination unit can be further improved when the trailers are equipped with an electronically controlled brake system.

A new cost-reduced generation (C-Version) of ABS with integral drive slip control, so-called Anti-wheel Spin Regulation (ASR) or Automatic Traction Control (ATC) for trucks and buses has been developed for the different requirements and standards of the world market and also especially for US vehicles. The system is based on field experiences with Anti-Lock Braking System (ABS) for commercial vehicles in Europe, North America and Japan as well as with integrated ASR. This paper describes the modular system configurations and components some new features and control modes. New engine controls are realized with a new pneumatic servo valve or via a data link according to SAE-standard J 1708/1922 for the US-market. In addition the paper deals with the technology and lay-out of the new ECU, its EMC, failure detection and failure mode principles, diagnostic means according to the standards ISO 9141 or SAE J 1708/1587, as well as a dedicated blink-code.

Vehicle and traffic safety improvement is one of the most important targets in the vehicle industry. The introduction of ABS for commercial vehicles, meanwhile standard in various countries, was one of the major safety improvements. This system, based on electronics, sensors and actuators shows what is achievable by controlling brakes of such heavy vehicles at the physical limits under various road conditions. With EBS (brake-by-wire) further safety features are integrated including active access of each wheel brake that allows, independent from the driver to apply the brakes to keep the vehicle stable. Electronic stability control as the overall vehicle control system integrated into EBS leads to a new generation of driver assistance concepts. The concept of Electronic Stability Control (ESC) integrated into EBS, simulation studies of vehicle behavior in critical situations, the control strategies and discussion of test results are the main content of this paper.

4- and 6-channel anti-lock braking systems (ABS) have been increasingly used in European trucks and buses since 1901. In a second generation of the WABCO-ABS the control of wheel slip caused by service brake or retarder is extended to operation control drive slip (ASR). For this, most components of the ABS are also applied. The higher integrated electronic control unit contains correspondingly extended software functions but less components than the first generation. A few additional valves and actuators are necessary to actuate a brake if only one driven wheel starts spinning or to reduce the engine power if all driven wheels develop unacceptable drive slip. This paper describes structural and functional principles of this control system for power-braked buses, trucks and tractors.

The heavy duty truck industry is looking for answers to make the brake system safer. One will be the Anti-lock Braking System (ABS). ABS is made for users. The flexible modular system allows for the application of main components to various vehicle configurations. Today's ABS does not only prevent locked wheels, it provides additional features such as a diagonal safety system and drive slip control (DSC). This paper addresses the unique features of the WABCO ABS with relation to its performance and the easy method of trouble shooting.