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Tires of modern commercial vehicles must meet a specific requirement profile, containing the economic aspects, ride comfort and driving safety, as well. These three primary criteria are discussed in this paper, whereby emphasis is placed on the force transmission behavior of commercial vehicle tires regarded as a variable directly associated to driving safety. At the same time, the influence of distinct parameters such as wheel load, road speed, tire inflation pressure, tread depth and coefficient of adhesion between tire and road on the lateral and braking force behavior is illustrated using steady state and dynamic measurements. They were carried out on real roads using a specially prepared mobile tire dynamometer, but on an indoor drum-type tire test stand, as well. In addition to the above mentioned parameter variations the differences of the results on account of the test method are analysed.

The Mercedes-Benz van range T1 was upgraded in 1989 according to market analysis. In this van range, performance, lower engine speed and greater fuel economy as well as other user-friendly and environment-protecting factors have led to a further optimization of all important commercial vehicle-specific criteria like economy, safety and environmental compatibility.

The aim of this paper is to analyse the component “steering” as a building block in an overall concept for the enhancement of active safety and driving comfort of commercial vehicles as well. The development steps will be elucidated regarding an electronically controlled power steering system, whereby the steering effort will be adapted to the dynamic parameters of the vehicle and thus to the prevailing driving conditions. Following the analysis of theoretical backgrounds, a concept for an electronically controlled power steering system was established that would comply to the stipulated technical specifications. In order to be able to select and determine the proper vehicle parameters for the micro-processor controlled steering system, the Mercedes-Benz driving simulator was put to use.

During the most recent past, contributions to anti-lock systems have been continuously published reflecting on the multi-functional significance of these systems only in a limited way. It seems essential therefore, to compare the primary criteria of functionality to the costs precisely. The technical solutions carried into effect during the past and the present orientated towards variously different criteria of optimization. The paper illustrates the particularities of the different control systems, like 2-, 4-and 6-channel systems with Individual Control, Select-Low Control or Modified Individual Control. The impact of the various ABS-philosophies on the directional control of heavy commercial vehicles will be analyzed, using driving maneuvers like “straight-ahead braking” or “braking in a turn” on homogeneous and split adhesion road surfaces.

Mercedes-Benz recognised early on the significance for the development of new components and systems of being able to conduct field trials in winter conditions. As a consequence, the company established a Winter Test Centre on the local airfield at Rovaniemi, Finland. The geographical location offers constant winter conditions for extended time periods. Road surfaces providing different degrees of adhesion, circular sections and gradients were created at the centre. Extracts of the work relating to the development of the anti-lock system ABS and the traction control ASR are presented as examples of a comprehensive programme of winter testing.

The tyre, as a link between vehicle and road, is an essential component to which great attention is paid when new vehicle concepts are being developed. The main criteria required of commercial vehicles are economy, safety and comfort- Increasing importance, as far as handling of commercial vehicles is concerned, is attached to the frictional behaviour of tyres. The influence of typical parameters, such as wheel load, road speed, inflation pressures of tyres, tyre tread depth and road surface as well as the effect of the scattering of the coefficient of adhesion of the different tyre makes are shown by means of steady-state and dynamic measurements. The directional control behaviour of a heavy commercial vehicle is analyzed with the aid of a simulation system developed by Mercedes-Benz. This includes computer-controlled test stands for tyres, brakes and axle kinematics as well as programmes for simulating the dynamics of a vehicle making use of the measured characteristics.

Systemized planning, increasing technological know-how and successful realization of electronic components suitable for use in commercial vehicles have considerably increased the technological standard of commercial vehicles over the last decade. Particular efforts were made to enhance traffic safety and relieve the stress on the driver through preventive measures on part of the vehicle. A primary consideration within the context of these objectives was the trouble-free controllability of acceleration and braking. It is thus possible to achieve a sufficient degree of lateral stability in the optimum wheel-slip range to guarantee not only the desired reduction in the demands on the driver, but also a high level of directional stability, steerability, shortest possible stopping distances and optimum tractional capacity under all tire-to-road adhesion conditions.

Since 1982 Daimler-Benz is the first commercial vehicle and bus manufacturer to offer modern anti-lock systems (ABS). After several years of development, anti-lock systems have technically matured to be installed upon request in vehicles with air brakes. The installation rate of this safety item has been steadily increasing ever since. The fundamental design and control philosophy of 4- and 6-channel anti-lock systems will be described. Besides a global analysis regarding the failsafe quotas of digitized electronics in road vehicles, the ABS-specific components will be looked at. The gain of safety achieved by the installation of ABS in commercial vehicles and buses will be presented with the aid of computer simulation. A 40-t-truck/trailer combination, with ABS, without ABS and with a partially defect system, will serve as an example to demonstrate the dynamic behavior during “Braking in a Straight Line” and “Braking in a Turn”

It is the goal of this paper, to discuss the impact of electronics on modern day commercial vehicles an buses. Seen from the position of advanced engineering of an European commercial vehicle manufacturer, the emphasis will be placed on the mechanical-electronical system itself, rather than the electronics themselves. User friendly, logic protected systems will minimize operator unfamiliarity and misapplication and will offer not only component control, but shortly the integration of all of these subsystems in the total vehicle control. Total vehicle control will be the ultimate result, when the driver, the truck and the environment are brought together. Such vehicles will be more responsive, safer and easier to drive than today's commercial vehicles and buses and offer a cost effective utilization of these new technologies to the customer.