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Identification of Automotive Cabin Design Parameters to Increase Electric Vehicles Range, Coupling CFD-Thermal Analyses with Design for Six Sigma Approach

FCA ITALY S.p.A.-Andrea Alessandro Piovano, Giuseppe Scantamburlo, Massimo Quaglino, Matteo Gautero
  • Technical Paper
  • 2020-37-0032
To be published on 2020-06-23 by SAE International in United States
The ongoing global demand for greater energy efficiency plays an essential role in the vehicle development, especially in case of electric vehicles (EVs). The thermal management of the full vehicle is becoming increasingly important, since the Heating, Ventilation, and Air Conditioning (HVAC) system has a significant impact on the EV range. Therefore the EV design requires new guidelines for thermal management optimization. In this paper, an advanced method is proposed to identify the most influential cabin design factors which affect the cabin thermal behavior during a cool down drive cycle in hot environmental conditions. These parameters could be optimized to reduce the energy consumption and to increase the robustness of the vehicle thermal response. The structured Taguchi’s Design for Six Sigma (DFSS) approach was coupled with CFD-Thermal FE simulations, thanks to increased availability of HPC. The first control factors selected were related to the thermal capacity of panel duct, dashboard, interior door panels and seats. Surface IR emissivity and solar radiation absorptivity of these components were then added to the study. Car glass with absorptive…
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Design of the Compression Chamber and Optimization of the Sealing of a Novel Rotary Internal Combustion Engine using CFD

Aristotle University of Thessaloniki-Savvas S. Savvakis, Elias Nassiopoulos, Dimitrios Mertzis, Zissis Samaras
  • Technical Paper
  • 2020-37-0007
To be published on 2020-06-23 by SAE International in United States
The increasing demand for lower fuel consumption and pollutant emissions favours the development of novel engine configurations. In line with this demand, the present contribution aims to investigate the sealing performance of a new concept rotary split-engine with a very promising thermal efficiency, a very low NOx emissions' level, and a much higher power density than any conventional internal combustion engine can. It uses the Atkinson cycle, a low-temperature combustion process and when it uses two pistons, symmetrically positioned around its shaft, it gives one power stroke every 180 degrees. The main focus of this work is to provide all the steps followed so far in order to ensure an efficient sealing and operation of the compression process of this engine, including the 1D & CFD simulations, CAD design & optimisation, and experimental campaign for verifying the digital results. The so-far investigation and experiments conclude that this new rotary engine can work with no oil lubrication inside the compression chamber and with much lower mechanical losses compared to the existing reciprocating engines.
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How Can Active Exhaust Systems Contribute to the Reduction of CO2 Emission and Comply with Future Pass-by Noise Limits?

Eberspaecher Exhaust Technology GmbH-Jan Krueger, Peter Wink, Maike Werner
  • Technical Paper
  • 2020-01-1534
To be published on 2020-06-03 by SAE International in United States
The pass-by noise limits of passenger vehicles according to ISO 362 / R51.3 will be further reduced by 2 dB in 2024 in Europe. Since the pass-by noise is substantially influenced by exhaust noise, the effort for the exhaust system needs to be increased. This results in systems with larger mufflers or higher backpressure. However, the more stringent CO2-emission targets require ever more efficient powertrains, which calls for rather lower backpressure to optimize the engine design. This paper describes, how compact active exhaust lines can support a design for low backpressure and high acoustic attenuation at the same time. For two passenger vehicle with gasoline engines, active exhaust lines are investigated in detail and the results are compared to the series production exhaust lines. Thus, in one exemplary case, the pass-by noise of a limousine could be reduced from 70 dB(A) to 68 dB(A) without any change in the vehicle design except the improved exhaust system.
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Advance CAE Methods for NVH Development of High Speed Electric Axle

AVL LIST GmbH-Mehdi Mehrgou, Julian Pohn, Bernhard Graf, Christoph Priestner
AVL Software and Functions Gmbh-Mathias Deiml
  • Technical Paper
  • 2020-01-1501
To be published on 2020-06-03 by SAE International in United States
By developing more electric vehicles more and more focus are to the noise and vibration from Electric Drive unit. Here a high-speed E-axle for premium class vehicle is being developed up to 30,000 rpm, with high power density and lightweight design which introduce new challenges. Benchmarking of different E-axle and vehicles lead to targets which can be used at the begin of development as subsystem targets. This paper shows first how these targets like tonal noise can be simulated. Then the CAE method is used to optimize the source and structure to improve the NVH. Different aspects like torque ripple, electric whine, gears whine and mounting are discussed.
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Robust Development of Electric Powertrain NVH for Compact Electric SUV

Hyundai Motor Company-Tae-Won Ha, Jin-Wook Huh, Sang-Kyu Choi, Dong-Wook Min, Chang-Kook Chae
Romax Technology-Annabel Abdy, Carsten Schmitt, Hanafy Mahmoud, Sharad Jain, Leon Rodrigues
  • Technical Paper
  • 2020-01-1503
To be published on 2020-06-03 by SAE International in United States
Electric vehicles (EV's) present new challenges to achieving the required noise, vibration & harshness performance (NVH) compared with conventional vehicles. Specifically, high-frequency noise and abnormal noise, previously masked by the internal combustion engine can also cause annoyance in an EV. Electric motor (E-motor) whine noise caused by electromagnetic excitation during E-motor operation is caused by torque ripple and stator local excitation. Under high speed and high load operating conditions, the sound level is low, however high frequency whine noise is a factor that can impair the vehicle level NVH performance. An example of a previously masked abnormal noise is a droning noise that can be caused by manufacturing quality variation of the spline coupling between the rotor shaft of the E-motor and the input shaft of the reducer, it is dominated by multiple higher orders of the E-motor rotation frequency. In this study, the high speed and high load condition whine noise problem was reproduced through electromagnetic and structural analysis, and the countermeasure (E-motor geometry refinements to reduce the excitations and mechanical system transfer path…
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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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A Generic Testbody for Low-Frequency Aeroacoustic Buffeting Phenomena

BMW Group, Munich, Germany-Rafael Engelmann, Christoph Gabriel
Vienna University of Technology-Stefan Schoder, Manfred Kaltenbacher
  • Technical Paper
  • 2020-01-1515
To be published on 2020-06-03 by SAE International in United States
Raising demands towards lightweight design paired with a loss of originally predominant engine noise pose significant challenges for NVH engineers in the automotive industry. Wall thickness reductions particularly emphasize low frequency contributors due to decreasing panel stiffness. From an aeroacoustic point of view, low frequency buffeting ranks among the most frequently encountered issues. The phenomenon typically arises from rooftop or side-window buffeting, structural transmission of hydrodynamic wall pressure fluctuations or, as indicated in this work, through rear vent excitation. A convenient 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 CFD. 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. Additionally, low frequency structural behavior strongly depends on appropriate boundary conditions being subject to manufacturing and mounting tolerances. The goal of this work is to develop, simulate and experimentally…
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Innovative Material Characterisation Methodology for Tyre Static and Dynamic Analyses

Applus + Idiada Group, Spain-Bharath Anantharamaiah
Applus IDIADA Group, Spain-Carlos Fidalgo
  • Technical Paper
  • 2020-01-1519
To be published on 2020-06-03 by SAE International in United States
Tyre structures are based on composite materials that constitute numerous layers, each providing specific properties to the tyre mechanic and dynamic behaviour. In principle, the understanding of the partial contributions of the individual layers requires knowledge of its mechanical properties. In case of non-availability of such critical information, it is difficult to perform tyre FE analyses. In the current work, a methodology is proposed to study the tyre static and dynamic behaviour to estimate its constituents properties based on the measured quasi-static responses of the tyre for certain specific loads. As a first step, a simplified tyre numerical model with standard rubber material properties is modeled that can substantively predict the necessary tyre static responses, i.e. radial, longitudinal and lateral stiffness. These responses are correlated with the physical tyre response that are measured using a kinematic and compliance (K&C) test rig in the laboratory. A Design of Experiments (DoE) study, followed by an optimization process, is performed by sampling the material properties of the rubbers to simulate the FE model and match the tyre responses…
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Design of a Multiwaves Vibration Filtering

LAUM (UMR CNRS 6613)-Adrien PELAT, François Gautier, Vicent Romero-garcia
VITESCO Technologies France SAS-Jules PLISSON, Thierry Bourdon
  • Technical Paper
  • 2020-01-1560
To be published on 2020-06-03 by SAE International in United States
In vibroacoustics, bandgap effects related to periodic and/or locally resonant architectural materials can lead to new types of structural vibration filters. This communication concerns periodic pipes used in industrial context. Such pipes are seen, as architectural structural waveguides in which bending, torsional, and longitudinal waves can propagate. To control the propagation of these vibrations and reduce their possible noise disturbance, Bragg or resonant band effects can be obtained by architecting the axial variations of the cross-section. As a result, a waveguide can be tuned to create stop bands with bandwidths large enough to make them interesting for industrial applications. For this purpose, dispersion relations are derived and analyzed based on the Floquet method and numerical Finite Element simulations. In many practical cases, all kinds of waves generally coexist due to the inevitable structural couplings. Therefore, the optimization of the geometric and mechanical characteristics of the structural couplings. Therefore, the optimization of the geometric and mechanical characteristics of the structure must be realized to attenuate several ( at least two) types of waves at the same…
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Using Statistical Energy Analysis to Optimize Sound Package for Realistic Load Cases

Audi AG-Christian März, Matej Glavac
ESI GmbH-Arnaud Caillet, Oussama Fatmi
  • Technical Paper
  • 2020-01-1525
To be published on 2020-06-03 by SAE International in United States
The statistical energy analysis (SEA) is widely used to support the development of the sound package of cars. This paper will present a model prepared to investigate the sound package of the new Audi A3 and its correlation against measurements. Special care was given during the creation of the model on the representation of the structure to able the analysis of structure borne energy flow on top of the classical airborne analysis usually done with SEA. The sound package is also detailed in the model to allow further optimization and analysis of its performance. Two real life load cases will be presented to validate the model with measurements. First, the dominating powertrain and second, a case with dominating rolling noise. An analysis of the contribution of the different source components and a way to diagnose the weak paths of the vehicle will be presented. The focus of this investigation is the application of optimally adjusted treatment.