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The monolithic DPF made of cordierite ceramic has unsatisfactory on his fatigue or long-term strength. A new design of configuration of plugs combined with the hexagonal channels shows a transversally isotropic property, and can remove the anisotropy of monoliths with square channels. This anisotropy is assumed to be one of main reasons for the failure of monoliths with square channels regarding the experimental results. Considering the honeycomb structure as a homogeneous material based on the Boltzmann continuum can't give the correct behaviour of this structure in a FEM simulation. Another homogenization procedure using the Cosserat theory has been discussed. The FEM stress analyses with structural detail-models show that the maximal tensile stresses in the monolith with square channels exist in the diagonal (i.e. 45°-) direction, or on the edges of channels. This feature is identical with what the theory has predicted and the experimental results have shown.

Rear axle steering systems electronically controlled and hydraulically actuated are discussed for commercial vehicles. With these steered axles, the major objective is to improve the manoeuvrability of these vehicles. With the aid of the steering strategy “Rear end Swing-out Compensation” it will be assured, that in two-axle, all-wheel steering trucks dangerous rear end swing-out effects, occuring primarily in low speed ranges, will not take place. In addition, it is possible to enhance the dynamic stability of two-axle trucks while braking on split adhesion road surfaces with the aid of specific control algorithms. Furthermore, the application of a rear axle steering system can suppress dangerous lateral oscillations of centre-axle trailers.

Salt Spray Test is being used since 1930’s to accelerate the corrosion testing of materials and to understand the longevity of applied coating. The sample in this kind of test is exposed to a salt mist in a controlled environment and its corrosion resistance is evaluated by measuring the corrosion rate. The Wet-Dry cycle in Salt Spray Test has the ability to simulate the drying and wetting which occurs in real driving scenario, leading to formation of a film of corrosion products which is useful in analyzing the kinetics of electrochemical reaction. Despite the advancement in severity of these tests to understand the atmospheric corrosion phenomena, they still consume time and resources. Secondly, sometimes these kind of tests do not consider into account the effect of Temperature, Humidity and other chemicals in play. Thus, numerical simulation plays a pivotal role in digitalizing the corrosion analysis to a certain extent.

The automotive world is progressing fast towards autonomous vehicles making sensors one of the critical components. There is a requirement for constant exchange of information between the vehicle and its surrounding environment, which is assisted by sensors such as Camera, LiDAR, and RADAR. However, exposure to harsh environmental conditions such as rain, dirt, snow, and bird droppings can hamper the functioning of the sensors and in turn interrupt accurate vehicle maneuvers. Sensor-cleaning mechanisms are required to be tested under various weather conditions and vehicle operating situations. Besides wind tunnel tests, digitalizing this whole process becomes important to take decision on design changes in early vehicle development stage. This work presents a digital methodology to test the LiDAR cleaning system in the advent of mud clearing at different vehicle speeds. The cleaning mechanism consists of a telescopic nozzle placed above the LiDAR translating back and forth.

The settings of adaptive suspension elements may be switched from a comfortable “soft” characteristic to a safe and “firm” characteristic. Thus the possibility is given to not only improve the ride comfort, but the dynamic driving behavior as well, since no compromise must be made between these two criteria when tuning the suspensions. Such systems seem to be very promising for commercial vehicles, as - because of their changing loading conditions - it is very difficult to design an optimal suspension system using conventional springs and dampers. This paper describes the influence of shock absorbers and air springs with variable characteristics on the ride comfort and the dynamic behavior of a 15-t-truck by investigations done with a simulation system. A series production vehicle without adaptive suspension elements serves as basis. At first the results of measurements and simulations are compared and show a very good concurrence.

Sunroof buffeting is examined experimentally and numerically in this paper. Despite the fact that some consider the simulation process for sunroof buffeting to be mature, there remain substantial uncertainties even in recently published methodologies. Capturing the frequencies and especially the sound pressure levels correctly is essential if CFD simulations are intended to be used during early stages of a car development process. Numerous experimental results of sunroof buffeting and the interior low-frequency characteristics of a 2013 Mercedes-Benz S-Class have been used to develop a simplified car model: a full-size S-Class model with slightly simplified geometries in the interior as well as at the exterior. To avoid the effects of numerous different materials in the interior, it is solely made from polyurethane and aluminum and built to maximize its structural rigidity and air-tightness.

The automotive industry is facing new emission regulations, changing customer preferences and technology disruptions. All have in common, that external aerodynamics plays a crucial role to achieve emission limits, reduce fuel consumption and extend electric driving range. Probably the most challenging components in terms of numerical aerodynamic drag prediction are the wheels. Their contribution to the overall pressure distribution is significant, and the flow topology around the wheels is extremely complicated. Furthermore, deltas between different rim designs can be very small, normally in the range of only a few drag counts. Therefore, highly accurate numerical methods are needed to predict rim rankings and deltas. This paper presents experimental results of four different production rim designs, mounted to a modified production car. An accurate representation of the loaded, deformed tire geometry is used in all calculations for comparable conditions between wind tunnel and CFD.

In this paper, the differences between a production car of the 2018 A-class and an early stage vehicle model with a mostly similar outer skin are examined experimentally and numerically. The aerodynamic development of vehicles at Mercedes-Benz is divided into several phases. When comparing force coefficients differences can be observed between these distinct hardware stages as well as when comparing steady state simulations to wind tunnel measurements. In early phases when prototype vehicles are not yet available, so-called aero foam models are used. These are well-defined full-sized vehicle models, as the outer skin is milled from Polyurethane. Important aerodynamic characteristics such as a motor compartment with a cooling module, deflecting axles with rotatable wheels and underbody covers are represented.

The current automotive market is dynamic, leading to complex functionalities being incorporated into the control software of various components like engine, gearbox, battery, E-motor etc. This results in utilization of virtual environments for software testing to reduce the development time. The virtual platforms under the category X-in-the-Loop (XiL) e.g. Software-in-the-Loop (SiL) and Hardware-in-the-Loop (HiL) use simulated models to achieve a desired test goal. These component models must be rigorously validated to ensure the quality of XiL-Testing. Thus, it is essential to define a model release process that maintains model quality irrespective of the modeling approach used and the user. One of the challenges is to choose an appropriate Error Metric (EM) that sets criteria for model release. This paper proposes a combination of Theil’s Inequality Coefficient (TIC) and Unscaled Mean Bounded Relative Absolute Error (UMBRAE) as the EM.

The paper describes a predictive tool for the determination of air and coolant temperatures and heat exchange resulting from the operation of heat exchangers, e.g., radiator or air-conditioner condenser in the underhood of automotive engines. The paper describes a detailed computational model where both the fluid streams are numerically solved and the phase change of the refrigerant is taken into account in a condenser simulation. An actual underhood simulation with interactions with a radiator is presented. A numerical simulation for a condenser is also presented. Reasonable agreement is shown with the test data.

The present study shows how the application of computational fluid dynamics can help to understand and optimize the flow field in a passenger compartment in order to achieve an optimum of thermal comfort for the occupants. The flow field and temperature distribution in a passenger compartment have been calculated using the commercial CFD program STAR-CD. In combination with a thermophysiological model for the passengers, the computational results are used to evaluate the thermal comfort of the occupants and compare different geometrical modifications. The computational mesh consisting of around 3 millions hexahedra cells resolves all geometrical details of the car cabin including the air ducts, air nozzles and louvers. Natural convection, heat conduction and radiation are taken into account. One standard climatisation mode, the winter heat-up mode has been simulated. A special emphasis of the numerical investigations is the optimization of the ventilation of the front and rear legroom.

The simulation of the driving performance of motor vehicles offers the possibility of analyzing the behavior of new commercial vehicles or new systems to be integrated into the vehicle, already before the stage of the first prototypes. Thus, simulation technology may contribute to shorten the time and costs needed for the development of new vehicles and new vehicle systems. As an example, this contribution describes the simulation of a commercial vehicle with adaptive suspension elements. The simulations were used to coarse-tune the suspension elements before installation and fine-tuning them in a prototype vehicle, and to define and optimize the control strategies of electronically controlled suspension systems. A comparison between the costs of the simulation and estimated costs of corresponding field tests substantiates the economical benefits of the simulation.

Computational models directly derived from data gained increased interest in recent years. Data-driven approaches have brought breakthroughs in different research areas such as image-, video- and audio-processing. Often denoted as Machine Learning (ML), today these approaches are not widely applied in the field of vehicle Noise, Vibration and Harshness (NVH). Works combining ML and NVH mainly discuss the topic with respect to psychoacoustics, traffic noise, structural health monitoring and as improvement to existing numerical simulation methods. Vehicle interior noise is a major quality criterion for today’s automotive customers. To estimate noise levels early in the development process, deterministic system descriptions are created by utilizing time-consuming measurement techniques. This paper examines whether pattern-recognizing algorithms are suitable to conduct the prediction process for a steering system.