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Multi-dimensional modelling of the flow and combustion promises to become a useful optimisation tool for IC engine design. Currently, the total simulation time for an engine cycle is measured in weeks to months, thus preventing the routine use of CFD in the design process. Here, we shall describe three tools aimed at reducing the simulation time to less than a week. The rapid template-based mesher produces the computational mesh within 1-2 days. The parallel flow solver STAR-CD performs the flow simulation on a similar time-scale. The package is completed with COVISEMP, a parallel post-processor which allows real-time interaction with the data.

Extensive crash sled testing and analysis has recently led to the development of a new HANS prototypes for use in FIA F1. The performance of HANS prototypes has been studied with various conditions of HANS design geometry and impact direction. The new HANS prototypes have been found to substantially reduce injurious motions and forces of the head and neck, and the new HANS is lighter, more compact, and performs better than the currently available HANS. Use of HANS by FIA F1 drivers has been initiated.

The design of automotive electronics is a highly cooperative, distributed process between car manufactures and suppliers. Due to significant increase of quality, cost, and time to market demands, several initiatives have been founded over the last years to address the increasing demand for standardization both for automotive electronics and vehicle based software. The German MSR consortium has concentrated on design tools and information exchange between manufacturers and suppliers, whereas the OSEK/VDX consortium has concentrated on the establishment of basic software components for open system architectures. To address future demands, these activities have to be consolidated and complemented by initiatives addressing the systematic improvement of the concurrent design processes as well as the appropriate qualification of engineering personnel.

The active safety of tractor / trailer-combinations plays an important role in regard to traffic safety in general. For improving the active safety of tractor / trailer-combinations, it is necessary to investigate the interactions between the towing vehicle and the trailer during braking maneuvers. This paper describes the ECE-regulations for the braking force distributions of tractor/full trailer- and tractor / semitrailer-combinations. The influence of different layouts of the braking systems within these regulations on the coupling forces between tractor and trailer and the driving performance of the units during braking is investigated. The dynamical behaviour of a tractor/full-trailer-combination and a tractor / semitrailer-combination are both discussed with the aid of simulations of the ISO-standard testing procedures “Braking in a turn” and “Braking straight ahead”.

In order to reduce the severity of injuries to pedestrians and cyclists, the sheetmetal contact zones of Mercedes-Benz cars are constructed of a yielding, smooth-surfaced design. Unfortunately, contradictory demands are made on some components. This is particularly true for the bumper in which avoiding or reducing the cost of repair requires a greater bumper height, overhang, and stiffness, which run counter to the requirements of pedestrian protection. Despite this conflict, however, the bumpers of recently developed Mercedes-Benz cars offer a high degree of pedestrian protection since they are faced with rigid foam. To assist in both mathematical and experimental pedestrian impact simulation, standard test dummies should be modified by reducing the stiffness at the waist in order to achieve a higher degree of faithfulness to human behaviour.

Safety considerations at Daimler-Benz are based on real-world accidents from which internal test procedures are derived. The example of the frontal collision is a clear illustration of this. In a crash against a flat, full car width barrier, a rare occurrence in real-world accidents, the impact energy is distributed over the entire width of the car. The majority of real-world frontal crashes, however, involve only partial overlap of the front. An adequately designed structure has to absorb the crash energy before it deforms the passenger compartment, i. e. by distributing the impact forces, and strategically located components must avoid the formation of blocks. In particular, the passenger compartment must be sufficiently stiff. Restraint systems and interior padding can only serve their protective purpose to their fullest if the survival space for the occupants is maintained intact.

Distribution of load has a major influence on type and severity of chest injuries. The introduction of the Hybrid III dummy into crash testing along with the requirement to measure sternum deflection for injury assessment has brought about the need to evaluate how well its thorax senses various loading conditions. Tests revealed that different load distributions, i.e. due to a diagonal shoulder belt or an airbag, did not produce the expected chest deflection patterns. This appears to be the result of both a relatively stiff sternum assembly and a nonsuitable design of the clavicle. Chest compression responses became more realistically when both, sternum and clavicle of the Hybrid II were mounted into the Hybrid Ill's thorax. As a consequence, this study suggests that the thorax of the Hybrid III dummy must be improved.

This report deals with the development and use of the Daimler-Benz Isohuman Simulation Model for the mathematical simulation of dummy behaviour in an impact environment. Designated ISM, this computer program package is capable of handling both automobile occupant and pedestrian kinematics. Daimler-Benz safety engineers use the ISM to evaluate new safety designs before performing actual laboratory tests. The ISM code uses the theoretical algorithm of Prof. Wittenburg. The dummy is represented by 11 rigid body elements. Realistic and accurate simulations are assured by the fact that a considerable number of functional and sophisticated algorithms were developed to involve the different interactions of dummy-to-belt or dummy-to-vehicle. In particular, considerable work is being done to introduce a more precise and realistic dummy and vehicle geometry.

The risk of head or chest injuries is usually evaluated by means of acceleration measurements using a dummy. Unfortunately, this data provides no information on load distribution over the contact areas which is often related to localized fractures of the bony structure. Therefore, new methods of measuring local forces were developed. 1. Pressure indicating devices attached to a dummy's face are capable of monitoring the local pressure during impact; foil's color change is interpreted by means of digital image analysis. 2. A velocity sensitive viscous tolerance criterion was calculated from the chest compression response of a dummy instrumented with strain gauges on the ribs. The application of advanced techniques in laboratory tests clearly supports the experience of improved protection potential through the use of airbag systems.

Daimler-Benz have developed an automatically/electronically controlled traction system, the 4MATIC. Great store has been set by active safety. This paper deals with the problems involved in 4-Wheel drive and analyzes the reasons which led to the 4MATIC concept. Depending on the conditions encountered, the drive components engage automatically one after the other in the sequence front-wheel drive - interaxle differential lock - rear axle differential lock. The engagement, and thus the approaching limits of driving dynamics, is indicated to the driver by an indicator lamp so that he can adjust to the deteriorated conditions in time. A further important advantage of this system is the automatic disengagement of the differential locks when braking so that the anti-lock braking remains fully effective.

Information on the driving stability can be obtained in the form of oversteer or understeer tendencies and acceleration limits on a circular path. Up to now the calculations have only been made on an ideal, even roadway. Significant dynamic characteristics, such as the tuning of the shock absorbers, which also play a role in evaluating the stability of a vehicle in a driving test, are thereby not included in the calculations. In this paper the unevenness of the roadway is taken into consideration in calculating steady state cornering tests. Different vehicle models can be evaluated in regard to their handling or active safety with the aid of the driver's steering actions required to keep the car on course.

The expected improved performance of a combined restraint system where an airbag supplements the conventional safety belt was not reflected in reduced g-values on the dummy's chest. However, by the distribution of force over the wider area of the airbag and the corresponding reduction of the specific pressure exerted by the three point belt, improved occupant protection is actually produced. Therefore, measurable quantities other than acceleration should be selected to evaluate the risk of chest injury, such as belt load or chest deflection. A new method to measure the deflection of dummy ribs with strain gauges has been developed. The resulting data indicate a significantly reduced chest deflection when a combined system is used.

The driving simulator is a computer-controlled tool to study the interface between driver and vehicle response under simulated traffic conditions. It permits a controllable, reproducible and cost-effective study of vehicle parameters up to the limits of active safety under non-dangerous conditions. It also permits driver participation in judging vehicle handling characteristics, and in evaluating the ‘feel’ of the steering, suspension, braking, and drive train, including the driver's environment, beginning with the initial vehicle design stages. The paper will describe fully the concept, design and planned activities as well as report on the new possibilities of using the driving simulator as a research and development tool.

Daimler-Benz considers safety belts as the fundamental and essential restraining system. The company began offering a Supplemental Restraint System option consisting of a driver airbag system and an emergency tensioning belt retractor for the passenger in December 1980. The functional reliability of the system has proven satisfactory.

A road simulation method has been developed to investigate ride comfort and fatique strength in the laboratory. A short description is given of the road profile generation technique used. The road to be simulated is recorded by driving the vehicle on the road and measuring the vertical accelerations and the forces of each spindle. In the laboratory the transfer behavior of the vehicle is determined with the aid of an identification technique. An iteration process is used. The simulation of the road profile and the forces is realised in the laboratory with multi-channel electrohydraulic equipments. Laboratory test results are shown and compared with road signals.