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One main goal of the automotive industry is to reduce the aerodynamic drag of passenger vehicles. Therefore, a deeper understanding of the flow field is necessary. Time-resolved data of the flow field is required to get an insight into the complex unsteady flow phenomena around passenger vehicles. This data helps to understand the temporal development of wake structures and enables the analysis of the formation of vortical structures. Numerical simulations are an efficient method to analyze the time-resolved data of the unsteady flow field. The analysis of the steady and unsteady numerical data is only relevant for aerodynamic developments in the wind tunnel, if the predicted temporal evolving structures of a passenger vehicle’s simulated flow field correspond to the structures of the flow field in the wind tunnel. In this study, time-resolved measurements of the empty wind tunnel and a notchback passenger vehicle in the wind tunnel are conducted.

The performance of environment perceiving sensors such as e.g. lidar, radar, camera and ultrasonic sensors is safety critical for automated driving vehicles. Therefore, one has to assess the sensors’ performance to assure the automated driving system’s safety. The performance of these sensors is however to some degree sensitive towards adverse weather conditions. A challenge is to quantify the effect of adverse weather conditions on the sensor’s performance early in the development of an automated driving system. This challenge is addressed in this work for lidar sensors. The lidar equation was previously employed in this context to derive estimates of a lidar’s maximum range in different weather conditions. In this work, we present a stochastic simulation framework based on a probabilistic extension of the lidar equation, to quantify the effect of adverse rainfall conditions on a lidar’s raw detection performance.

Minimizing the lap time for a given race track is the main target in racecar development. In order to achieve the highest possible performance of the vehicle configuration the mutual interaction at the level of assemblies and components requires a balance between the advantages and disadvantages for each design decision. Especially the major shift in the focus of racecar powerunit development to high efficiency powertrains is driving a development of lean boosted and rightsized engines. In terms of dynamic engine behavior the time delay from requested to provided torque could influence the lap time performance. Therefore, solely maximizing the full load behavior objective is insufficient to achieve minimal lap time. By means of continuous predictive virtual methods throughout the whole development process, the influence on lap time by dynamic power lags, e.g. caused by the boost system, can be recognized efficiently even in the early concept phase.

With increasing levels of driving automation, the perception provided by automotive environment sensors becomes highly safety relevant. A correct assessment of the sensors’ perception reliability is therefore crucial for ensuring the safety of the automated driving functionalities. There are currently no standardized procedures or guidelines for demonstrating the perception reliability of the sensors. Engineers therefore face the challenge of setting up test procedures and plan test drive efforts. Null Hypothesis Significance Testing has been employed previously to answer this question. In this contribution, we present an alternative method based on Bayesian parameter inference, which is easy to implement and whose interpretation is more intuitive for engineers without a profound statistical education. We show how to account for different environmental conditions with an influence on sensor performance and for statistical dependence among perception errors.

Longitudinal models are used to evaluate different vehicle-engine concepts with respect to driving behavior and emissions. The engine is generally map-based. An explicit calculation of both fluid dynamics inside the engine air path and cylinder combustion is not considered due to long computing times. Particularly for dynamic certification cycles (WLTC, US06 etc.), dynamic engine effects severely influence the quality of results. Hence, an evaluation of transient engine behavior with map-based engine models is restricted to a certain extent. The coupling of detailed 1D-engine models is an alternative, which rapidly increases the model computation time to approximately 300 times higher than that of real time. In many technical areas, the Fourier transformation (FT) method is applied, which makes it possible to represent superimposed oscillations by their sinusoidal harmonic oscillations of different orders.

The open jet wind tunnel is a widespread test section configuration for developing full scale passenger cars in the automotive industry. However, using a realizable nozzle cross section for cost effective aerodynamic development is always connected to the presence of wind tunnel effects. Wind tunnel wall interferences which are not present under open road conditions, can affect the measurement of aerodynamic forces. Thus, wind tunnel corrections may be required. This work contains the results of a CFD (Computational Fluid Dynamics) approach using unsteady Delayed Detached Eddy Simulations (DDES) to evaluate wind tunnel interferences for open jet test sections. The Full Scale DrivAer reference geometry of the Technical University of Munich (TUM) using different rear end shapes has been selected for these investigations.

Automotive engineering processes are dynamic, iterative and driven by changes. Reasons for changes on development artifacts are manifold, but the result is a new evolution step which may influence all, some, or just a single development artifact. Consequently, research on impact analysis put forth approaches to assess the adverse effects of changes. However, understanding and implementing functional changes and its consequences in the safety domain is often aggravated by dependencies between different types of development artifacts, scattered in various (tool) formats. Safety properties may change depending on the type of a modification. Thereby, connected analyses like fault trees, Failure Modes and Effects Analysis (FMEA), and safety concepts cannot be reused easily if the artifacts on which they are based on are affected by changes. In this paper we suggest a new difference analysis approach which allows a (semi-)automated comparison of safety work products based on models.

In this work we extended the findings from a previous study by the authors on the mechanisms and influence factors of deposit formation in urea-based selective catalytic reduction systems (SCR) [1]. A broader range of operating conditions was investigated in detail. In order to quantify the boundary conditions of deposition, a representative set of deposits was studied during formation and decomposition. A box of heat resisting glass was equipped with a surrogate mixing element to monitor solidification timescales, temperatures and deposit growth. A chemical analysis of the deposits was performed using thermogravimetry. The depletion timescales of individual deposit components were systematically investigated. A moderate temperature increase to 350 °C was deemed sufficient to trigger fast decomposition of deposits formed below 250 °C.

Today, body vibration energy of passenger cars gets dissipated by linear working shock absorbers. A new approach substitutes the damper of a passenger car by a cardanic gimbaled flywheel mass. The constructive design leads to a rotary damper in which the vertical movement of the wheel carrier leads to revolution of the rotational axis of the flywheel. In this arrangement, the occurring precession moments are used to control damping moments and to store vibrational energy. Different damper characteristics are achieved by different induced precession. From almost zero torque output to high torque output, this damper has a huge spread. Next to the basic principal, in this paper an integration in the chassis, including a constructive proposal is shown. A conflict with high torque and high angular velocity leads to a special design. Moreover concepts to deal with all vehicle situations like yawing, rolling and pitching are shown.

The German funded project ARAMiS included work on several demonstrators one of which was a multicore approach on large scale software integration (LSSI) for the automotive domain. Here BMW and Audi intentionally implemented two different integration platforms to gain both experience and real life data on a Hypervisor based concept on one side as well as using only native AUTOSAR-based methods on the other side for later comparison. The idea was to obtain figures on the added overhead both for multicore as well as safety, based on practical work and close-to-production implementations. During implementation and evaluation on one hand there were a lot of valuable lessons learned about multicore in conjunction with safety. On the other hand valuable information was gathered to make it finally possible to set up a cost model for estimation of potential overhead generated by different integration approaches for safety related software functions.

Strategies for weight reduction have driven the noise treatment advanced developments with a great success considering the already mastered weight decreases observed in the last years in the automotive industry. This is typically the case for all soft trims parts. In the early 2010's a typical european B-segment car soft trims weights indeed 30 to 40% less than in the early 2000's years. The main driver behind such a gap has been to combine insulation and absorption properties on a single part while increasing the number of layers. This product-process evolution was conducted using a significant improvement in the simulation capacities. In that sense, several studies presenting very good correlation results between Transmission Loss measurements and finite elements simulations on dashboard or floor insulators were presented. One may consider that those kinds of parts have already achieved a considerable improvement in performance.

This study deals with the experimental investigation of the mechanical properties of a lithium-ion pouch cell and its modelling in an explicit finite element simulation code. One can distinguish between ‘macroscopic’ and ‘microscopic’ modelling approaches. In the ‘macroscopic’ approach, one material model approximates the behaviour of multiple inner cell layers. In the ‘microscopic’ approach, which is used in the present study, all layers and their interactions are modelled separately. The cell under study is a pouch-type lithium-ion cell with a liquid electrolyte. With its cell chemistry, design, size and capacity it is usable for automotive applications and can be assembled into traction batteries. One cell sample was fully discharged and disassembled, and its components (anode, cathode, separator and pouch) were examined and measured by electron microscopy. Components were also tensile tested.

Multicore-based ECUs are increasingly used in embedded automotive software systems to allow more demanding automotive applications at moderate cost and energy consumption. Using a high number of parallel processors together with a high number of executed software components results in a practically unmanageable number of deployment alternatives to choose from. However correct deployment is one important step for reaching timing goals and acceptable latency, both also a must to reach safety goals of safety-relevant automotive applications. In this paper we focus at reducing the complexity of deployment decisions during the phases of allocation and scheduling. We tackle this complexity of deployment decisions by a mixed constructive and analytic approach.

The anti-lock braking system (ABS) is a widespread driver assistance system which allows a short braking distance while simultaneously maintaining the stability and steerability of the car. Vehicles with electric single-wheel drive offer many possibilities of improving the energy efficiency and the braking performance during ABS braking. In this paper, two different ways of including the electric machines in the ABS are analyzed in detail: the damping of torsional drive train vibrations in combination with recuperation and the dynamic split of the braking torque, where the hydraulic braking torque is kept constant and the dynamic modulation of the braking torque is performed by the electric machines. The damping algorithm is developed on the basis of a linearized model of the drive train and the tire-road contact by using state feedback and pole placement methods. Simulation results with a detailed multi-body system show the effectiveness of the control algorithms.

New power train concepts in the automobile industry will decisively change the familiar car acoustics. Secondary acoustic noise sources will be unmasked and dominate the driver's sound experience. The most important secondary noise source is the air conditioning (AC) system. Before a favorable AC sound can actively be designed, it is necessary to identify the acoustic noise sources and find means to influence them. This paper focuses on the AC outlet module which is, apart from the control unit, the only part visible to the customer. Typical acoustic spectra of flowed-through outlets show a characteristic tonality at about 3000 Hz. The knowledge of its aeroacoustic source mechanisms, the inherent implications for the customer and corrective measures especially in automobile surroundings has been limited so far. To analyze this phenomenon in detail, a simplified model outlet that shows the basic aeroacoustic behavior of a series production outlet was constructed and investigated.

With the introduction of the ISO26262 automotive safety standard there is a burden of proof to show that the processing elements in embedded microcontroller hardware are capable of supporting a certain diagnostic coverage level, depending on the required Automotive Safety Integrity Level (ASIL). The current mechanisms used to provide actual metrics of the Built-in Self Tests (BIST) and Lock Step comparators use Register Transfer Level (RTL) simulations of the internal processing elements which force faults into individual nodes of the design and collect diagnostic coverage results. Although this mechanism is robust, it can only be performed by semiconductor suppliers and is costly. This paper describes a new solution whereby the microcontroller is synthesized into a large Field Programmable Gate Array (FPGA) with a test controller on the outside.

The potential of determining the change of injury severity in the accident event taking passive as well as active measures into account at the vehicle (integral systems) are at present limited to pedestrian protective systems. Therefore, an extension of the existing methods for the application with common integral systems (front protection, side protection, etc.) is suggested. Nowadays the effectiveness of passive safety systems is determined in crash tests with very high accident severities. However, approximately 90% of real-world accidents have a lower accident severity as the required crash tests. Thus, this paper will present a method calculating the effectiveness of such an integral system based on real-world accident data. For these reasons, this paper is presenting a method for a more valid prediction of injury severity. The German In-Depth Database GIDAS allows clustering the accident event in relevant car-to-car scenarios.

GTL (Gas-To-Liquid) fuel is well known to improve tailpipe emissions when fuelling a conventional diesel vehicle, that is, one optimized to conventional fuel. This investigation assesses the additional potential for GTL fuel in a GTL-dedicated vehicle. This potential for GTL fuel was quantified in an EU 4 6-cylinder serial production engine. In the first stage, a comparison of engine performance was made of GTL fuel against conventional diesel, using identical engine calibrations. Next, adaptations enabled the full potential of GTL fuel within a dedicated calibration to be assessed. For this stage, two optimization goals were investigated: - Minimization of NOx emissions and - Minimization of fuel consumption. For each optimization the boundary condition was that emissions should be within the EU5 level. An additional constraint on the latter strategy required noise levels to remain within the baseline reference.

Fully variable valve trains provide comprehensive means of adjustment in terms of variable valve timing and valve lift. The efficiency of the engine is improved in the operating range and in return, an increasing complexness of the mechanical design and control engineering must be handled. For optimization and design of these kinds of complex systems, detailed simulation models covering different physical domains, i.e. mechanics, hydraulics, electrodynamics and control are needed. Topic of this work is the variable valve train named Audi valvelift system (AVS) e.g. used in the Audi 2.8l V6 FSI engine. The idea of AVS is to use different cam lobes at different operating points. Each intake valve can be actuated by a large and a small cam. For full load, the two inlet valves are opened by the large cam profile - ideal for high charge volumes and flow speeds in the combustion chamber. Under partial load, the small cam profiles are used.

Helmholtz-resonators are discussed in technical acoustics normally in conjunction with attenuation of sound, not with amplification or even production of sound. On the other hand everybody knows the sound produced by a bottle, when someone blows over the orifice. During the investigation of the sound produced in body gaps it was found that the underlying flow physics are closely related to the Helmholtz-resonator. But different from the typical Helmholtz-resonator generated noise – as for example the blown bottle or, from the automotive world, the sun roof buffeting – there is no fluid resonance involved in the process. For body gaps the random pressure fluctuation of the turbulent boundary layer is sufficient to excite the acoustic resonance in the cavity. The sound generation is characterized by a continuous rise in sound pressure level with increasing velocity, the rise is proportional to U with varying exponents.