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Over the past 30 years, the computer-aided engineering (CAE) tools have been applied extensively in the automotive industry. In order to accelerate time-to-market while coping with legal limits that have become increasingly restrictive over the last decades, CAE has become an indispensable tool covering all major fields in a modern automotive product design process. However, when tackling complex real-life engineering problems, the computational models might become rather involved and thus less efficient. Therefore, the overall trend in the automotive industry is currently heading towards combined approaches, which allow the best of the both worlds, namely the experimental measurement and numerical simulation, to be merged into one integrated scheme. In this paper, the so-called patch transfer function (PTF) approach is adopted to solve coupled vibro-acoustic problems. In the PTF scheme, the interfaces between fluid and structure are discretised in terms of patches.

Raising demands towards lightweight design paired with a loss of originally predominant engine noise pose significant challenges for NVH engineers in the automotive industry. From an aeroacoustic point of view, low frequency buffeting ranks among the most frequently encountered issues. The phenomenon typically arises due to structural transmission of aerodynamic wall pressure fluctuations and/or, as indicated in this work, through rear vent excitation. A possible workflow to simulate structure-excited buffeting contains a strongly coupled vibro-acoustic model for structure and interior cavity excited by a spatial pressure distribution obtained from a CFD simulation. In the case of rear vent buffeting no validated workflow has been published yet. While approaches have been made to simulate the problem for a real-car geometry such attempts suffer from tremendous computation costs, meshing effort and lack of flexibility.

Comfort and well-being have always been connected with a flawless interior acoustic, free of any background noise or BSR, (buzz, squeak and rattle). BSR noises dominate the interior acoustic and represent one of the main sources for discomfort often causing considerable warranty costs. Traditionally BSR issues have been identified and rectified through extensive hardware testing, which by its nature intensifies toward the end of the car development process. In the following paper the integration of a virtual BSR validation technique in a modern development process by the use of appropriate CAE methods is presented. The goal is to shift, in compliance with the front loading concept, the development activities into the early phase. The approach is illustrated through the example of an instrument panel, from the early concept draft for single components to an assessment of the complete assembly.

Virtual testing has grown to be an efficient tool in vehicle passive safety design. Most simulations currently are deterministic. Since the responses observed in real-life and standardized tests are greatly affected by scatter, a stochastic approach should be adopted in order to improve the predictability of the numerical responses with respect to the experimental data. In addition, an objective judgement of the performance of numerical models with respect to experimental data is necessary in order to improve the reliability of virtual testing. In the European VITES & ADVANCE project the software tool Adviser was developed in order to fulfil these two requirements. With Adviser, stochastic simulations can be performed and the quality of the numerical responses with respect to the experimental can be objectively rated using pre-defined and user-defined objective correlation criteria. The software Adviser was used to develop a stochastic HybridIII 50th% Madymo numerical model.

Reductions of hardware costs as well as implementations of new innovative functions are the main drivers of today's automotive electronics. Indeed more and more resources are spent on adapting existing solutions to different environments. At the same time, due to the increasing number of networked components, a level of complexity has been reached which is difficult to handle using traditional development processes. The automotive industry addresses this problem through a paradigm shift from a hardware-, component-driven to a requirement- and function-driven development process, and a stringent standardization of infrastructure elements. One central standardization initiative is the AUTomotive Open System ARchitecture (AUTOSAR). AUTOSAR was founded in 2003 by major OEMs and Tier1 suppliers and now includes a large number of automotive, electronics, semiconductor, hard- and software companies.

The importance of the automotive interior as a characteristic feature in the competition for the goodwill of the customer has increased significantly in recent years. Whilst there are established, more or less efficient CAE processes for the solution of problems in the areas of occupant safety and service strength, until now the implementation of CAE in themes such as dimensional stability, warpage and corrugation1 of plastic parts has been little investigated. The developmental support in this field is predominantly carried out by means of hardware tests. Real plastic components alter their form as a result of internal forces often during the first weeks following production. The process, known as “creep”, can continue over an extended period of time and is exacerbated by high ambient temperatures and additional external loads stemming from installation and post assembly position.

Within the pre-development phase of a vehicle validation process, the role of computational simulation is becoming increasingly prominent in efforts to ensure thermal safety. This gain in popularity has resulted from the cost and time advantages that simulation has compared to experimental testing. Additionally many of these early concepts cannot be validated through experimental means due to the lack of hardware, and must be evaluated via numerical methods. The Race Track Simulation (RTS) can be considered as the final frontier for vehicle thermal management techniques, and to date no coherent method has been published which provides an efficient means of numerically modeling the temperature behavior of components without the dependency on statistical experimental data.

BMW can look back on 20 years of research activities on hydrogen propulsion systems. Hydrogen fuel is the only means of offering pure driving pleasure on the basis of a sustainable energy loop. As the hydrogen era is still quite a while away the BMW Energy Strategy „Via Natural Gas to Hydrogen” has been developed. The first step was to build series-production compressed natural gas (CNG) cars back in 1995. By switching to liquefied natural gas (LNG) not only is the cruising range tripled but technologically the final stepping-stone is reached in preparing the way for liquefied hydrogen. BMW's automotive and drive technology for hydrogen is now available and ready to move out of the laboratory on to the road. At Munich Airport a BMW „Clean Energy” car is already providing shuttle services. Its fuel is supplied by the world's first public filling station for liquefied hydrogen.

A comprehensive experimental study was conducted to investigate human movements when entering a vehicle. The primary goal of this study was to understand the influence of environmental changes on entry motions selected by a driver to enter a vehicle. The adjustable hardware setup “VEMO” (Variable Entry Mockup) was used for the experiments. With VEMO it is possible to simulate different types and classes of vehicle configurations. Around 30 test persons of different anthropometry participated in the experiments. The visual measurement system VICON was used for motion capturing, motion data cleaning and biomechanical analysis. The results corroborate the theory of leading body parts (LBPs) i.e. body parts that control targeted movement of the entire body. It could be demonstrated how motion patterns of LBPs, including spatial and dynamic characteristics such as orientation and velocity, respond to modifications of the geometrical environment.

As the popularity of vehicle navigation systems rises, incorporating Real Time Traffic Information (RTTI) has been shown to enhance the systems' value by helping drivers avoid traffic delays. As an innovative premium automaker, BMW has developed a testing process to acquire and analyze RTTI data in order to ensure delivery of a high quality service and to enhance the customer experience compared to audible broadcast services. With a methodology to obtain valid and repeatable RTTI data quality measurements, BMW and its service partner, Clear Channel's Total Traffic Network (TTN), can improve its offered service over time, implement corrective measures when appropriate, and confidently ensure the service meets its premium objectives. BMW has partnered with TTN and SoftSolutions GmbH to implement a traffic data quality process and software tools.

The paper will introduce the concept of intelligent automotive system services as an essential pattern for forthcoming Electric/Electronic (E/E) architectures. System services are infrastructure-related, having vehicle-wide functionalities with one central part (master) and optionally several peripheral parts (clients) as counterparts in every ECU. System services support the reliable operation, efficient administration and maintenance of car functions over the entire life cycle. System services constitute vehicle-wide, distributed functionalities. Therefore, a consistent, interoperable and scalable implementation and integration strategy is outlined. In addition, synergies to the standard core as well as to the AUTOSAR concept will be described.

The average weight of a car has increased significantly in recent years due to higher crash requirements and demands in standard equipment. Therefore, BMW has decided to use aluminium for the body front end of the new BMW 5-series. During the paint process, the 6XXX-alloys currently adopted for the body front end exhibit a considerable increase in yield strength in the E-coat dryer. The increase of strength, the so-called paint bake response of 6XXX-alloys, needs to be fully exploited to meet the increasing demand of future passive safety concepts.

For car manufacturers, seating comfort is becoming more and more important in distinguishing themselves from their competitors. There is a simultaneous demand for shorter development times and more comfortable seats. Comfort in automobile seats is a multi-dimensional and complex problem. Many current sophisticated measuring tools were consulted, but it is unclear on which factors one should concentrate attention when measuring comfort. The goal of this paper is to find a model in order to predict the overall seating discomfort based on body area ratings. Besides micro climate, the pressure distribution appears to be the most objective measure comprising with the clearest association with the subjective ratings. Therefore an analysis with three different test series was designed, allowing the variation of pressure on the seat surface. In parallel the subjects were asked to judge the local and the overall sensation.

Especially in horizontal applications of thermoplastic body-panels occurs a conflict between the required thermal stability (generally achieved with short glass fibers) and the high level surface finish as the reinforcements worsen the surface texture. The sandwich-molding procedure for bigger body-panels, developed further at BMW, offers an innovative solution to this problem. Two materials, one with good surface finish properties (material A) and another with glass fiber reinforcement (material B), are coinjected in a single process step. The result is a part with class-A surface (only material A visible at the surface), advanced mechanical and thermal properties. Additionally to an outstanding surface finish the body-panel exhibits small thermal expansion relevant for reduction of gaps to bordering parts.

A top-of-the-range car customer not only expects exceptional vehicle design and quality but also a driving experience, which is out of the ordinary. Very harmonious interaction between vehicle dynamics and the steering system is required to offer clients such a consistent driving experience through generations of vehicle models. In this paper the basic properties of a premium driving experience are explored. It is shown that outstanding handling limits are a prerequisite, although most customers never experience such driving situations. In fact, on-center behavior is most crucial in enabling clients to experience part of premium driving performance, and the steering system is the key factor in delivering appropriate feedback to the driver by means of steering torque. Development procedures are presented to achieve the goals described above.

The thermal prediction of a vehicle under-body environment is of high importance in the design, optimization and management of vehicle power systems. Within the pre-development phase of a vehicle's production process, it is important to understand and determine regions of high thermally induced stress within critical under-body components. Therefore allowing engineers to modify the design or alter component material characteristics before the manufacture of hardware. As the exhaust system is one of the primary heat sources in a vehicle's under-body environment, it is vital to predict the thermal fluctuation of surface temperatures along corresponding exhaust components in order to achieve the correct thermal representation of the overall under-body heat transfer. This paper explores a new method for achieving higher accuracy exhaust surface temperature predictions.

The SI-engine has a disadvantage in fuel economy compared with a DI-Diesel engine. One of the major effects is the throttle-driven load control with its pumping losses. The main target is to reduce these losses in the thermodynamic process with a throttle-free load control. BMW has developed fully variable valve trains as a possible technical solution to realise a load control by regulating the valve lift and the closing time of the inlet valve. The essential variability can be achieved by fully variable mechanical valve trains or mechatronic systems both showing a robust running behavior in emissions and cyclic fluctuations. The camshaft driven mechanical system is based on the technology of the BMW Double-VANOS system. An additional variability makes it possible to shift the valve lift continuously in order to control the valve closing. The highest variability is given by a system with each valve being controlled seperatly.

This paper presents an integrated simulation process which has been performed in order to assess the riding comfort performance of a vehicle seat system virtually. Present methods of seat comfort design rely on the extensive testing of numerous hardware prototypes. In order to overcome the limitations of this expensive and time-consuming process, and to fasten innovation, simulation-based design has to be used to predict the seat comfort performance very early in the seat design process, leading to a drastic reduction in the number of physical prototypes. The accurate prediction of the seat transfer function by numerical simulation requires a complete simulation chain, which takes into account the successive stages determining the final seat behaviour when submitted to vibrations. First the manufacturing stresses inside the cushion, resulting from the trimming process, are computed.