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The paper begins with an overview of the history of ABS for commercial vehicles followed by a brief description of the technology of the BOSCH ABS at the time it went into mass production in 1981. Subsequently it describes the field experiences with ABS including the experiences of drivers and operators. These experiences are reflected in the equipment which BOSCH offers today. Additional functions such as ASR (traction control) have been integrated. The paper provides an overview of the functions available today and their implementation. The paper concludes with a discussion on potential continued developments and an attempt to describe the systems which will be required by the mid 9os.

Misfiring of the engine can cause damage to the catalyst within short time and increase emissions. Under misfiring conditions, unburned fuel and oxygen are pumped into the catalyst, where its combustion heavily increases the temperature. For this reason there is a demand for fast detection of misfiring. Once judged, one can take countermeasures to avoid further temperature rise. Two methods of misfire detection with the prospect of future use in series production are discussed. A first approach uses the trace shape of the λ-sensor signal for evaluation. The second approach uses the speed fluctuations of the engine for detection. Efficient algorithms give the possibility of misfire detection in the full load-speed range with reasonable effort to protect the catalyst. However there will remain some misfire conditions, increasing the emissions above regulation limits, that cannot be detected by those methods.

Current vehicle concepts necessitate the multiple measurement of several variables required by separate electronic systems in the motor vehicle. There is the need to make sensors bus capable by the incorporation of electronic components in new definition concepts, in other words to make them multiply usable. Such bus concepts are at the present time taking concrete shape. The step of introducing electronics - especially digital - to the measuring point may simultaneously be used to considerably improve utilization of the information content of sensor structures using means of indivdual, digital correction to a greater level than has until now been technically possible. There remains the demand for high stability and reproducibility of the sensor properties over time. These signal preprocessing and information condensation processes on the spot also satisfy the need to relieve the central control units.

The article describes the methods, which are employed in order to ensure high performance, safety and quality of ABS and ASR. System behaviour is evaluated and optimized by computer simulation. Moreover, a real-time simulator has been developed by which the consequences of hardware defects can be investigated systematically, Despite the increasing use of simulation the testing of vehicles remains the most important tool for system evaluation. For that purpose, a digital data acquisition system has been developed and objective evaluation criteria have been established. In order to achieve high product quality the Failure Mode and Effect Analysis (FMEA) is carried out at an early phase of development. Another prerequisite for high product quality is thorough durability and endurance testing before release of production.

Despite the tough environmental conditions facing electronic systems in commercial vehicles, electronics is gaining ground also in these applications. In the drive sector it improves the operation of the main and auxiliary drives, upgrades fuel efficiency and reduces emission pollutant levels. It enhances safety by preventing wheel spinning in braking and acceleration. Electronic displays reduce the number of single indications otherwise needed, thus making for more clarity in information for the driver and facilitating the driver's task. Self-diagnosing and integrated emergency operation (“limp home”) capabilities are to ensure availability, a factor of special importance in commercial vehicles. A data interface standardized as widely as possible would allow add-on systems to be coupled easily and flexibly.

Increasingly stringent requirements regarding exhaust emission, fuel consumption, driveability and comfort have led to an accelerated introduction of electronically controlled systems, the complexity of which can best be handled by microcomputers, these being the basis of all modern electronic control units. These electronic control units are usually installed in the passenger compartment, due to the need for moderate conditions in respect of temperature, vibration, moisture and dust. However because of the increasing variety of systems the available space for the installation of these control boxes has become smaller and smaller whilst the complexity of the wire harness has led to increased costs and electromagnetic interference problems. As a result there is an increasing demand for electronic control units (ECU) which can be installed in the engine compartment.

The Bosch ABS for passenger cars which has been in production since 1978 has been described in numerous publications. Following the gathering of extensive experience with the Bosch ABS and its installation in the different models of passenger car, the concept has been revised with various upgrade levels in order to further optimize braking performance on µ-split road surfaces with different right/left adhesion coefficients, in order further to improve the operation of the system when braking on very slippery road surfaces and also to adapt the control algorithm to four-wheel-drive vehicles with differential locks.

Mathematical modelling has proved to be a valuable tool for understanding the performance of diesel injection systems. There are several programs for the simulation of conventional injection equipment, but up to now it has been very expensive to simulate new concepts of injection equipment. Therefore a general program system for simulation of transient hydraulic processes - especially in diesel injection systems - has been developped. By this system, any new injection equipment can be simulated user-friendly and without needing to write new programs. The differential equations are solved by mathematical methods, which promise stability in all conditions and offer short calculation times. Since 1983 the program system has been applied to a lot of non-conventional and conventional injection systems and has proved its reliability.

Modern agricultural tractors are equipped with a hitch control system. These may be mechanical-hydraulic, hydraulic-hydraulic, or electronic-hydraulic. With the variety of design options open to the tractor manufacturer, it is important to select the system which best fits the manufacturer and end user. This paper presents a comprehensive comparison of each system. Robert Bosch has had many years experience in the design and manufacture of components for hitch systems, and hopes to help designers choose the approach best suited for them.

The usage of Electronic Diesel Control is increasing with todays stringent emissions regulations. This requirement also necessitates that such systems be versatile to meet the needs of the engine/vehicle manufacturer. EGR, start of injection, and fuel delivery can be electronically controlled. Depending on the design goals of the manufacturer any one or two of these can be controlled for partial and all of them for full Electronic Diesel Control. The development and application process has several critical areas. These include, development of the sensors, application of the different subsystems, failure warning and failure mode operation. All of these must be combined if design goals are to be met. As the capabilities of electronics increase it follows that electronic vehicle systems will also improve. Today impressive results have been achieved with systems that are in full or pilot production.