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A Novel Option for Direct Waste Heat Recovery From Exhaust Gases of Internal Combustion Engines

Universita degli Studi dell Aquila-Davide Di Battista, Roberto Cipollone PhD, Roberto Carapellucci PhD
  • Technical Paper
  • 2020-37-0004
To be published on 2020-06-23 by SAE International in United States
Among the different opportunities to save fuel and reduce Co2 emissions from internal combustion engines, great attention has been done on the waste heat recovery: the energy wasted is, in fact, almost two thirds of the energy input and even a partial recovery into mechanical energy is really promising . Usually, thermal energy recovery has been referred to a direct heat recovery (furtherly expanding the gases expelled by the engine thanks to their high pressure and temperature) or an indirect one (using the thermal energy of the exhaust gases – or of any other thermal streams discharged into the atmosphere – as upper source of a conversion power unit which favour a thermodynamic cycle of a working fluid ). Limiting the attention to the exhaust gases, a novel opportunity can be represented by directly exploiting the residual pressure and temperature of the flue gases through an Inverted Brayton cycle (IBC), in which the gases are expanded at a pressure below the environmental one, cooled down and then recompressed to the environmental pressure. Considering the thermodynamic…
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A Detailed Finite Element Thermal Analysis of a 18650 Format Battery Cell for Automotive Applications

University of Modena and Reggio Emilia-Saverio Giulio Barbieri, Valerio Mangeruga, Dario Cusati, Matteo Giacopini, Francesco Cicci
  • Technical Paper
  • 2020-37-0022
To be published on 2020-06-23 by SAE International in United States
This paper presents a methodology for the thermal analysis of a cylindrical Li-Ion battery cell. In particular, the 18650 format is considered. First, an electrical current drain cycle is applied to measure the electrical internal resistance of the cell and to estimate the consequent thermal energy release. A battery cell is then dissected and the inner structure is reproduced in detail with the adoption of microscopic images. By this way, the heat generation areas and the different thermal paths are correctly identified. Thermal Finite Element analyses are performed faithfully reproducing the inner geometry of the cell, and different cooling strategies are compared. The numerical results are then validated versus experimental evidence obtained considering the thermal behaviour of a small section, made by three cells, of a water cooled battery pack. The proposed approach can drive the design process towards more efficient battery pack cooling strategies. The numerical model may be then applied to perform thermo-structural analyses and, consequently, structural failures of the battery cells might be predicted.
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Reduction of the Effect of the Creep Groan Brake Excitation in a Comercial Vehicle

IDIADA Automotive Technology SA-Angel Sanchez
  • Technical Paper
  • 2020-01-1530
To be published on 2020-06-03 by SAE International in United States
One of the results generated by the stick-slip intermittent motion of a brake at the friction interface is the Creep Groan Noise which is a low frequency self-excited vibration, normally less than 220 Hz. This local vibration generated between the brake couple, is transmitted through the suspension system until the passengers of the vehicle in form of vibration and noise. This paper presents a methodology that combines testing and numerical models in order to 1) detect the source of the Creep Groan, 2) create a correlated numerical model and 3) produce countermeasures that reduce the amplitude of the noise at occupant positions. The vehicle under investigation was a commercial vehicle employing air-actuated brake drums. From testing, global vehicles modes and displacements under operational conditions were respectively investigated by means of Operational Deflection Shapes and Real Time Animation. These techniques allowed to prove the existence of a feedback loop with a positive gain that excites a suspension resonance mode, creating an unstable shaking effect in the whole vehicle. In-service data suggest that the brake actuation system…
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Development of the Active Sound Generation Technology using Motor Driven Power Steering System

Hyundai Motor Co.-Kyoung-Jin Chang
Mdynamix AG-Leonhard Angerpointner, Dominik Schubert, Matthias Niegl
  • Technical Paper
  • 2020-01-1536
To be published on 2020-06-03 by SAE International in United States
As original engine sound is usually not enough to satisfy the driver’s desire for the sporty and fascinating sound, active noise control (ANC) and active sound design (ASD) have been great technologies in automobiles for a long time. However, these technologies which enhance the sound of vehicle using loud speakers or electromagnetic actuators etc. lead to the increase of cost and weight due to the use of external amplifier or external actuators. This paper presents a new technology of generating a target sound by the active control of a permanent magnet synchronous motor (PMSM) which is already mounted in vehicle. Firstly, an algorithm of this technology, called an active sound generation (ASG), is introduced with those signal conversion process, and then the high frequency noise issue and its countermeasure are presented. Secondly, ASG test bench is designed using a motor driven power steering (MDPS) system and then it is checked if ASG has any influence on an original function of MDPS. Thirdly, motor-induced vibration is measured in the transfer path and then the appropriate level…
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Sliding Mode Controlled Half Car Suspension System with Magnetorheological Damper

Anna University-AROCKIA SUTHAN SOOSAIRAJ, ARUNACHALAM K
  • Technical Paper
  • 2020-01-1540
To be published on 2020-06-03 by SAE International in United States
Attenuation of vibrations caused by the road undulance conditions are tedious and very much related to human health and vehicle handling problems. One of the promised approaches to solving these problems in a vehicle suspension system is the use of effective controllers. In this paper, the sliding mode controller (SMC) is designed and used to control the magnetorheological (MR) damper. The performance of the proposed controller is verified by incorporating the controller in a half car vehicle suspension model. In a suspension damper design, Modified Bouc-Wen model is used to characterize the hysteretic behaviour of MR damper parameters. The voltage control algorithm is used to convert the desired force into the varied voltage input to the MR damper. The fail-proof advantage of MR damper is analysed by comparing the results of uncontrolled MR suspension with a passive system. In order to limit the pitch angle and to achieve the improved ride comfort and stability of the vehicle, the vertical displacement of the front and rear body of the half-car model is controlled by the SMC…
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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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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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Impact of Manufacturing Inaccuracies on the Acoustic Performance of Sound Insulation Packages With Plate-like Acoustic Metamaterials

Hamburg University of Applied Sciences-Felix Langfeldt, Wolfgang Gleine
  • Technical Paper
  • 2020-01-1562
To be published on 2020-06-03 by SAE International in United States
Thin plate-like metamaterials (e.g. membrane-type acoustic metamaterials or inhomogeneous plates) have a high potential for improving the sound transmission loss of sound insulation packages, especially in the challenging low-frequency regime. These types of metamaterials have been previously shown to achieve very high sound transmission loss values which can exceed the corresponding mass-law values considerably. However, like many other metamaterial realizations, their extraordinary acoustical performance relies on the periodicity of the sub-wavelength sized unit cells. In particular, for plate-like acoustic metamaterials (PAM) most theoretical and numerical investigations assume a perfect placement of equal added masses - an idealization which cannot be achieved in industrial manufacturing of these metamaterials. This contribution investigates the impact of randomized inaccuracies that can occur in manufacturing on the sound reduction behavior of PAM. First, a numerical model of a finite sized PAM is validated using sound transmission loss measurement data. Then, the simulation model is modified to incorporate randomly varying geometrical parameters of the added masses (such as mass placement, size, etc.). The parameters are randomized according to a Gaussian distribution…
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A Bridging Technology to Combine Test and Simulation With In-Situ TPA

Head acoustics GmbH-Matthias Wegerhoff, Roland Sottek, Haiko Brücher
  • Technical Paper
  • 2020-01-1574
To be published on 2020-06-03 by SAE International in United States
To shorten development processes and to secure decisive product properties as early as possible, new methods are required for product development. These must be able to generate the maximum information about the future product out of the data available at the respective development step. Computer-aided engineering (CAE) is therefore becoming increasingly important. CAE makes it possible to predict product properties at an early development stage and to partly replace physical prototypes with numerical models (virtual prototypes). However, the transition from experiment-based methods to numerical approaches is a big step. Often, purely-numerical examinations are only possible to a limited extent because of the following reasons: complex modeling, missing data or input data with major uncertainties, lack of expertise, or development processes not suitable for numerical methods. Therefore, this paper addresses a "bridging technology" that combines the advantages of experiment-based and numerical methods and allows optimal evaluation of the properties of the product to be developed. For this purpose, an exciting subsystem with its structural dynamics is represented by Equivalent Forces (EF) determined based on measured accelerations…
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Numerical Analysis of the Influences of Wear on the Vibrations of Power Units

Robert Bosch GmbH-Yashwant kolluru
  • Technical Paper
  • 2020-01-1506
To be published on 2020-06-03 by SAE International in United States
Numerical Analysis of the Influences of Wear on the Vibrations of Power Units 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 The prime factor, which influences vibrations of electro-mechanical drives, is wear at the components. This paper discusses the numerical methods developed for abrasion, vibration calculations and the coupling between wear and NVH models of drive unit. Wear is a complex process and understanding it is essential for vibro-acoustics. The paper initially depicts finite element static model used for wear calculations. The special subroutines developed, aids in coupling the wear equations, various contact and friction formulations to the numerical model. The vibration domain model initially, focuses on calculations of mechanical excitation's at the gear shafts, which are generated via a nonlinear dynamic model. Furthermore, the bearings are studied for the influences on its stiffness and eventually its impact on harmonics of the drive trains. Later, free and forced vibrations of the complete drive train are simulated via steady-state dynamic…