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Multidisciplinary Investigation of Truck Platooning

Altair-Bastian Schnepf, Christian Kehrer, Christoph Maeurer
  • Technical Paper
  • 2020-37-0028
To be published on 2020-06-23 by SAE International in United States
In the age of environmental challenges and with it, the demand for increasing energy efficiency of commercial vehicles, truck platooning is discussed as a promising approach. The idea is several trucks forming an automated convoy – with the lead truck sending out acceleration, braking and steering signals for the following trucks to react accordingly. The benefits address fuel savings, traffic capacity, safety requirements and convenience. In our study, we will motivate why platooning requires a multidisciplinary approach in the sense of connecting different modeling and simulation methods. The simulation topics covered are aerodynamic analysis, vehicle-to-vehicle (V2V) communication, radar antenna placement and virtual drive cycle test for the energetic evaluation of a truck platoon in comparison to a single truck. Aerodynamic analyses are conducted using a transient Lattice Boltzmann approach on GPUs capturing the complex vehicle wake interactions for different platooning distances with acceptable computational effort. Thereby, a generic truck convoy, consisting of three vehicles, is considered for distance intervals between 7 and 40 meters. From these computations for each vehicle look-up-tables are derived for interpolation…
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Simulation of Driving Cycles by Means of a Co-Simulation Framework for the Prediction of IC Engine Tailpipe Emissions

Exothermia SA-Vasileios Tziolas, Nikolaos Zingopis
Politecnico di Milano-Gianluca Montenegro, Angelo Onorati, Gianluca D'Errico, Tarcisio Cerri, Andrea Marinoni
  • Technical Paper
  • 2020-37-0011
To be published on 2020-06-23 by SAE International in United States
The current European legislation concerning pollutant emissions from IC engine vehicles is very stringent and demanding. In addition, the CO2 fleet emission must obey to a significant reduction path during the next decade, to cope with the prescribed targets recently agreed. The prediction of pollutant emissions from IC engines has been a challenge since the introduction of the emission regulation legislation. During the last decade, along with the more tightening limits and increased public concern about air quality, the capability of simulating different operating conditions and driving cycles with an acceptable computational effort has become a key feature for modern simulation codes. The role of 1D thermo-fluid dynamic simulation models is extremely important to achieve this task, in order to investigate the performances of the next generation of IC engines working over a wide range of operating conditions, under steady-state and transient conditions. This work is based on the idea of integrating two different 1D simulation tools in a co-simulation environment, realizing a strict numerical coupling between the two codes. The main goal is to…
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Challenges in Vibroacoustic Vehicle Body Simulation Including Uncertainties

BMW AG-Marinus Luegmair, Michal Styrnik
Technical University of Munich / BMW AG-Johannes D. Schmid
  • Technical Paper
  • 2020-01-1571
To be published on 2020-06-03 by SAE International in United States
For many years, the model quality and frequency range of NVH simulation with Finite Element (FE) models have been increased and led to a better vehicle quality. Nowadays, model range and quality are on such a high fidelity and there is often no further improvement, even with extreme modelling and computation effort. So in order to improve the quality of predictions, the next step is to take uncertainties into account. With this approach there are many challenges on the way to valid and useful simulation models and they can be divided into three areas: the input uncertainties, the propagation of uncertainties through the FE model and finally the statistical output quantities. Each of them must be investigated to choose sufficient methods for a valid and fast prediction of vehicle body vibroacoustics. With a discrimination of different types of uncertainties it can be shown that the dimensionality of the corresponding random space is tremendously high. Therefore, a substantial reduction of the dimensionality is crucial. Next step is to choose a proper method to model uncertainties and…
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Efficient Modeling and Simulation of the Transverse Isotropic Stiffness and Damping Properties of Laminate Structures using the Finite Element Method

BMW Group-Vlad Somesan, Endre Barti
Fraunhofer Lbf-Thilo Bein
  • Technical Paper
  • 2020-01-1573
To be published on 2020-06-03 by SAE International in United States
The Noise Vibration and Harshness (NVH) characteristics and requirements of vehicles are changing as the automotive manufacturers turn their focus from developing and producing cars propelled by internal combustion engines (ICE) to electrified vehicles. This new strategic orientation enables them to offer products that are more efficient and environmentally friendly. Although electric powertrains have many advantages compared to their established predecessors they also produce new challenges that make it more difficult to match the new requirements especially regarding NVH. Electric motors are one of the most important sources of vibrations in electric vehicles. In order to address the new challenges in developing powertrains that match the acoustic comfort requirements of the customers and also shape the development process as efficiently as possible, car manufacturers use numerical simulation methods to identify NVH problems as early in the design process as possible. Numerically describing the dynamic properties of electric motor components such as the stator or rotor is proving to be especially difficult as they contain heterogeneous parts that have viscoelastic orthotropic or transverse isotropic stiffness and…
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Root Cause Analysis and Structural Optimization of E-Drive Transmission

AVL LIST GmbH-Thomas Resch
AVL-AST d.o.o.-Borislav Klarin, Ivan Grozdanovic, Denis Pevec
  • Technical Paper
  • 2020-01-1578
To be published on 2020-06-03 by SAE International in United States
We face a growing demand for so-called eAxles (electric axle drive) in vehicle development. An eAxle is a compact electric drive solution for full electric vehicles (and P4 hybrids) with integrated electric machine and transmission. The transmission can be rather simple using fixed gear with cylindrical gear steps but increasing demands on power and speed range as well as efficiency increase its complexity with planetary stages or switchable gear steps. Such an electro-mechanic system has different behavior than the classical ICE-driven powertrains, for example regarding NVH, where high frequency and tonal noise from gear whining and electro-magnetic excitation is an important comfort issue that needs to be understood and controlled. As knowledge base for such drives is currently low, development needs to be supported by methodologies, which are not only on high predictive level for NVH responses, but also allow a detailed understanding and insight into the causes and reasons of a certain behavior to identify noise effects and to accelerate learning for such systems. In addition, such methods should lead to the possibility to…
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Hybrid Approach for the Assessment of Paths in Pass by Manoeuver

Centro RIcerche Fiat S.C.p.A.-Domenico Amodeo
Centro Ricerche Fiat S.C.p.A.-Marco Danti, Massimo Biasiolo
  • Technical Paper
  • 2020-01-1550
To be published on 2020-06-03 by SAE International in United States
Current vehicle regulations demand for a challenging decrease in the overall exterior noise as a benefit for the health of citizens and road users. New limits have been implemented in UN R51.03 (based on ISO 362-1:2015) to reduce the emitted noise both at constant speed and in full load so as to cover most of the real urban driving conditions. In order to achieve those targets the carmakers have to refine the trim of their vehicle and an experimental approach can take place too late. This paper shows a method for the pass by noise simulation exploiting the numerical transfer functions and a library of experimentally characterized sources with the aim to reduce the noise and find out a better tradeoff between costs and effectiveness of the modifications. Moreover a simple software tool for the treatment of the data and to ease the workflow has been created and used for the rank assessment of the different paths.
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Numerical Investigation of Narrow-Band Noise Generation by Automotive Cooling Fans

Chalmers University of Technology-Omar Fares, Huadong Yao
Volvo Car Group-Chenyang Weng, Linus Zackrisson, Magnus Knutsson
  • Technical Paper
  • 2020-01-1513
To be published on 2020-06-03 by SAE International in United States
Axial cooling fans are commonly used in electric vehicles to cool batteries with high heating load. One drawback of the cooling fans is the high aeroacoustic noise level resulting from the fan blades and the obstacles facing the airflow. To create a comfortable cabin environment in the vehicle, and to reduce exterior noise emission, a low-noise installation design of the axial fan is required. The purpose of the project is to develop an efficient computational aeroacoustics (CAA) simulation process to assist the cooling-fan installation design. This paper reports the current progress of the development, where the narrow-band components of the fan noise is focused on. Two methods are used to compute the noise source. In the first method the source is computed from the flow field obtained using the unsteady Reynolds-averaged Navier-Stokes equations (unsteady RANS, or URANS) model. In the second method, the azimuthal modes of the flow field obtained using the steady RANS with the moving reference frame model are treated as the sound source. While the first method is able to resolve any…
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Multi-domain NVH Model for the Complete Electro-mechanical Power Unit

Robert Bosch GmbH-Yashwant kolluru, Rolando Doelling PhD
  • Technical Paper
  • 2020-01-1584
To be published on 2020-06-03 by SAE International in United States
Multi-domain NVH Model for the Complete Electro-mechanical Power Unit Yashwant Kolluru, Rolando Doelling eBike Department Robert Bosch GmbH Kusterdingen, Germany yashwant.kolluru@de.bosch.com rolando.doelling@de.bosch.com Lars Hedrich Institute of Informatics Goethe University Frankfurt Frankfurt, Germany hedrich@em.informatik.uni-frankfurt.de Acoustics and vibrations are amongst the foremost indicators in perceiving the quality of power units. Analyzing these factors is vital to improve the performances of electro-mechanical systems. This paper deals with development of a generic simulation method enabling the multi-domain vibro-acoustic modelling for the drive trains. Excitation's for these systems majorly arise from the electric motor and mechanical gears. The paper initially depicts a flexible gear model for gear whining, which are generated for reasons like gear tooth bending. The forces generated from gear mesh (lumped parameter model) to gear components (multi-body model and nonlinear static model) and the excitations resulting from motor model are coupled for the frequency domain analysis of complete drive train. Additionally, paper discusses the influences of these forces on bearings (dynamic implicit model) and effect of bearing deformations on the harmonics of drive unit. Furthermore, velocities on…
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Squeak&Rattle - New Equivalent Static Load (ESL) based on Dynamic Distortion in all Body Openings from both Test and Simulation

AFRY-Viktor Jönsson
BETA CAE Nordic AB-Mohamed Zaben
  • Technical Paper
  • 2020-01-1556
To be published on 2020-06-03 by SAE International in United States
The body stiffness has a major impact on the Squeak&Rattle (S&R) performance of a car. Since the body structure of electrical/automated cars will differ clearly from traditional bodies, an enhanced requirement is needed to limit the distortion in the closure openings. The new requirement can be derived from a complete vehicle simulation using the deformation of the diagonals in the closure openings. This simulation includes different test tracks by using the dynamic road load data which can be obtained from a multi body simulation of a complete vehicle. Since the requirement needs to be applied early in the development only an untrimmed body model (BIG) is available, which can be used for a simplified static load. This paper shows a new approach of defining an equivalent static load (ESL), which considers both the reduction from a complete vehicle to a BIG and from a dynamic load to a static load. The approach is based on the comparison of the deformation in the diagonals of all closure openings between the dynamic simulation of a complete trimmed…
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Resabtors - Advanced Multi-Material Muffler Designs for Clean Air Applications

Umfotec-Ralf Buck
Umfotec GmbH-Ingo Krebs
  • Technical Paper
  • 2020-01-1554
To be published on 2020-06-03 by SAE International in United States
The development and production of resonators on the charged air side of combustion engines require profound base of knowledge in designing, simulating and the production of such parts in different materials (aluminum, copper, stainless steel and technical plastic). As combustion engines are under constant discussion, this existing knowledge base should be used for other applications within and outside the automotive industry. Very quickly it became apparent that new challenges often require completely new solutions, designs and materials to meet the requirements of flow noise reducing parts. For example, for clean air applications mufflers based on “special treated foams” and “meta-materials” can be introduced. These materials offer new potentials for tuning of the frequency range and allow improved broad banded flow noise attenuation. Such parts are named “Resabtors” in order to take respect of the different flow noise attenuation principles resonation and absorbing. Since in almost all applications the installation space is very limited, it was necessary to combine these two principles into one component. This results into significant challenges to identify the properties of the…