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How Should Innovative Combustion Engines be Developed, Operated and Built in Order to Turn From Climate Sinners Into Climate Savers?

Hamburg University of Applied Sciences-Victor Gheorghiu
  • Technical Paper
  • 2020-37-0009
To be published on 2020-06-23 by SAE International in United States
KEYWORDS – Strict Atkinson Cycle implementation, Extended Expansion Cycle, VCR, Enhanced Thermal Conversion Efficiency, High Pressure Turbocharging, Hydrogen DI, stoichiometric mixture, new load control ABSTRACT The Ultra-Downsizing is introduced as an even higher stage of downsizing of ICE. Ultra-downsizing will be implemented here by means of real Atkinson cycles using an asymmetrical crank mechanisms with continuous VCR capabilities, combined with two-stage high-pressure turbocharging and very intensive intercooling. This will allow an increase of ICE performance while keeping the thermal and mechanical strain strength of engine components within the current usual limits. Research Objective The principal purpose of this investigation is to analyze and evaluate a strict implementations of Atkinson cycles on Internal Combustion Engines (ICE) by means of the VCSR asymmetrical crank mechanisms (VCSR means Variable Compression and Strokes Ratios) for DI-Hydrogen-fueled (or with H2-CNG blends) case. The VCSR will be presented in two constructive variants. The mechanical loads as torque and forces within the VCSR crank mechanism will be presented and analyzed in some engine operation points. Methodology A small size SI NA MPI…
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Development, System Integration and Experimental Investigation of an Active HVAC Noise Control System for a Passenger Car

Fraunhofer Institute LBF-Jonathan Millitzer, Valentin Mees, Christopher Ranisch
Hyundai Motor Company-Joong-Kwan Kim, Jinmo Lee, ChiSung Oh, Kang-Duck Ih
  • Technical Paper
  • 2020-01-1538
To be published on 2020-06-03 by SAE International in United States
Current developments in the automotive industry such as electrification and consistent lightweight construction increasingly enable the application of active control systems for the further reduction of noise in vehicles. As different stochastic noise sources such as rolling and wind noise as well as noise radiated by the ventilation system are becoming more noticeable and as passive measures for NVH optimization tend to be heavy and construction space intensive, current research activities focus on the active reduction of noise caused by the latter mentioned sources. This paper illustrates the development, implementation and experimental investigation of an active noise control system integrated into the ventilation duct system of a passenger car. Making use of a model-based design process, the development is based upon a holistic numerical simulation model integrating a reduced order acoustic model derived from finite element simulations as well as simplified loudspeaker and microphone characteristics. The numerical simulation assists the selection of a suitable loudspeaker microphone configuration, taking into account the available installation space and the integration of low-cost loudspeakers and MEMS microphones. The ventilation…
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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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Inverse Characterization of Vibro-Acoustic Subsystems for Impedance-Based Substructuring Approaches

BMW Group-Matthieu Grialou, Arnaud Bocquillet
INSA-Lyon / LVA-Jean-Louis GUYADER, Nicolas Totaro PhD
  • Technical Paper
  • 2020-01-1582
To be published on 2020-06-03 by SAE International in United States
Substructuring approaches are helpful methods to solve and understand vibro-acoustic problem involving systems as complex as a vehicle. In that case, the whole system is split into smaller, simpler to solve, subsystems. Substructuring approaches allow mixing different modelling “solvers” (closed form solutions, numerical simulations or experiments). This permits to reach higher frequencies or to solve bigger systems. Finally, one of the most interesting features of substructuring approaches is the possibility to combine numerical and experimental descriptions of subsystems. The latter point is particularly interesting when dealing with subdomains that remain difficult to model with numerical tools (assembly, trim, sandwich panels, porous materials, etc.). The Patch Transfer Functions (PTF) method is one of these substructuring approaches. It condenses information (impedance matrix) of subsystems on their coupling surfaces. In case of a passive subsystem (no source inside), the condensed impedance matrix is the only information needed to couple it to the rest of the system. Classically, this matrix is computed using numerical modeling methods. In the present works, a method to experimentally characterize this impedance matrix is…
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Time Domain Full Vehicle Interior Noise Calculation from Component Level Data by Machine Learning

Mercedes-Benz AG-Dimitrios Ernst Tsokaktsidis, Clemens Nau
Technical University of Munich-Steffen Marburg
  • Technical Paper
  • 2020-01-1564
To be published on 2020-06-03 by SAE International in United States
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), these approaches are not widely applied in the field of vehicle Noise, Vibration and Harshness (NVH) yet. Related works mainly discuss the topic with respect to structural health monitoring, psychoacoustics, traffic noise and as improvement to existing numerical simulation methods. Vehicle interior noise is a major quality criterion for today’s automotive development. 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 improve the prediction process for a steering system. Starting from operational measurements, a procedure to calculate the sound pressure level in the passenger cabin is developed and investigated. Component time domain data serves as basis for the computation. The important inputs are determined by a correlation analysis. Input selection is followed by data reduction. After preprocessing, a supervised learning environment is established.…
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Concept Study on Windshield Actuation for Active Control of Wind Noise in a Passenger Car

Fraunhofer Institute LBF-Thorsten Koch, Jonathan Millitzer, William Kaal PhD, Georg Stoll, Matthias Schmidt
Hyundai Motor Company-Joong-Kwan Kim, Jinmo Lee, ChiSung Oh, Kang-Duck Ih
  • Technical Paper
  • 2020-01-1535
To be published on 2020-06-03 by SAE International in United States
The windshield is an integral part of almost every modern passenger car. Combined with current developments in the automotive industry such as electrification and the integration of lightweight material systems, the reduction of interior noise caused by stochastic and transient wind excitation is deemed to be an increasing challenge for future NVH measures. Active control systems have proven to be a viable alternative compared to traditional passive NVH measures in different areas. However, for windshield actuation there are neither comparative studies nor actually established actuation concepts available to the automotive industry. Based upon a numerical simulation of an installed windshield of a medium-sized car, this paper illustrates a conceptual study of both the evaluation of optimal positioning as well as a consideration of different electromechanical activation measures. A simulation model of the installed windshield is gained from an experimental modal analysis of both the windshield in free-free condition as well as in its installed configuration. The experimental data serves the frequency domain model update process of a finite element model of the installed windshield. A…
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Modelling and Numerical Simulation of the Noise Generated by Automotive Turbocharger Compressor

TU Wien-Manfred Kaltenbacher, Clemens Freidhager, Stefan Schoder
  • Technical Paper
  • 2020-01-1512
To be published on 2020-06-03 by SAE International in United States
An effective technology to reduce emission and fuel-consumption is the use of turbochargers. A turbocharger increases the air pressure at the inlet manifold of the engine by using the waste energy from the exhaust gas to drive a turbine wheel that is linked to the compressor through a shaft. Besides the use in combustion engines, fuel cell systems for vehicle applications also need compressed air to achieve high power densities. Thereby, in fuel cell systems the noise emission of turbochargers is no longer masked by the combustion engine. In operation, the main noise sources are generated by the flow in the compressor and the different noise phenomena need to be understood in order to efficiently reduce the emitted noise and increase comfort. A huge potential in order to achieve this goal is a simulation based investigation to study in detail the flow mechanism, the aeroacoustic sources and its sound propagation. However, the actual physical source mechanism as rotational and pulsation noise as well as hiss / whoosh noise is currently not fully understood. Therefore, the…
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Multi-Frequency Model Reduction for Uncertainty Quantification in Computational Vibroacoustics of Automobiles

Groupe PSA-Justin Reyes, Laurent Gagliardini
Université Paris-Est Marne-la-Vallée-Christophe Desceliers, Christian Soize
  • Technical Paper
  • 2020-01-1583
To be published on 2020-06-03 by SAE International in United States
This paper deals with the vibroacoustics of complex systems over a broad frequency band of analysis. The system under consideration is composed of a complex structure coupled with an internal acoustic cavity, such as the one encountered in automotive industry. The complex structure is defined by a complex geometry, constituted of heterogeneous materials and of two types of structural levels: a stiff main part and numerous flexible sub-parts. In such a structure, the vibroacoustics model is represented by the usual global-displacements elastic modes associated with the main part, and by numerous local elastic modes, which correspond to the preponderant vibrations of the flexible sub-parts. However, in the framework of automobile vibroacoustic modeling, the main difficulty is the interweaving of the global displacements with the numerous local displacements, which introduce an overlap of the usual three frequency domains (low- (LF), medium- (MF), and high frequency (HF)). In the automotive industry, computational vibroacoustic models are used for predicting the internal noise levels. However, the dimension of computational vibroacoustic models is very high. In this paper, a computational…
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A Priori Analysis of Acoustic Source Terms from Large-Eddy Simulation in Turbulent Pipe Flow

Graz University of Technology-Johannes Tieber, Helfried Steiner
  • Technical Paper
  • 2020-01-1518
To be published on 2020-06-03 by SAE International in United States
The absence of combustion engine noise pushes increasingly attention to the sound generation from other, even much weaker, sources in the acoustic design of electric vehicles. The present work focusses on the numerical computation of flow induced noise, typically emerging in components of flow guiding devices in electro-mobile applications. The method of Large-Eddy Simulation (LES) represents a powerful technique for capturing most part of the turbulent fluctuating motion, which qualifies this approach as a highly reliable candidate for providing a sufficiently accurate level of description of the flow induced generation of sound. Considering the generic test configuration of turbulent pipe flow, the present study investigates in particular the scope and the limits of incompressible Large-Eddy Simulation in predicting the evolution of turbulent sound sources to be supplied as source terms into acoustic analogies, which have been proposed for the computation of the acoustic pressure field. To this end, a comprehensive a priori analysis of fully resolved flow fields obtained from Direct Numerical Simulations (DNS) was carried out for different Reynolds numbers. The analysis of the…
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Design and Optimization of a Resonant Type Acoustic Meta-Material for Sound Attenuation

Mecanum Inc-Noureddine Atalla
Mecanum Inc.-Patrick Bouche, raymond panneton
  • Technical Paper
  • 2020-01-1559
To be published on 2020-06-03 by SAE International in United States
Considering the fact that most conventional acoustic materials have reached their limit in terms of performance, it is important to find new ways to attenuate sound. This study describes the design and optimization of the sound absorption and sound insulation of an Acoustic Meta-Material (AMM) based on embedding acoustic resonators in a porous material. Previous works have already addressed this kind of AMM, mostly using simulations and tests in impedance tubes. This work develops and tests the studied AMM at medium-scale (60 x 60 cm², tested in acoustic cabin). The proposed solutions are specifically used to attenuate low frequency noise are easily manufacturable. Theoretical and experimental investigations are conducted to optimize and validate the concepts under realistic density and volume constraints. Starting with analytical solutions, using transfer matrix method, and numerical simulations, using FEM/BEM module of NOVA software, various concepts are optimized in terms of sound absorption and sound transmission. Optimized concepts are fabricated and tested in a medium-scale acoustic test chamber to demonstrate their augmented acoustic insulation performance.