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Numerical Analysis of the Influences of Wear on the Vibrations of Power Units

Goethe-Universität-Lars Hedrich
Robert Bosch GmbH-Yashwant Kolluru, Rolando Doelling
  • 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…
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Analytical Prediction of Acoustic Emissions From Turbocharger Bearings

Loughborough Univ-Nader Dolatabadi, Homer Rahnejat
Loughborough Univ.-Ramin Rahmani
  • Technical Paper
  • 2020-01-1504
To be published on 2020-06-03 by SAE International in United States
Turbochargers are progressively used in modern automotive engines to enhance engine performance and reduce energy loss and adverse emissions. Use of turbochargers along with other modern technologies has enabled development of significantly downsized internal combustion engines. However, turbochargers are major sources of acoustic emissions in modern automobiles. Their acoustics has a distinctive signature, originating from fluid-structure interactions. The bearing systems of turbochargers also constitute an important noise source. In this case, the acoustic emissions can mainly be attributed to hydrodynamic pressure fluctuations of the lubricant film. The developed analytical model determines the lubricant pressure distribution in the floating journal bearings used mainly in the modern turbocharges. This allows for an estimation of acoustic emissions. The use of such an analytical approach is computationally efficient when compared with full numerical analysis approaches, whilst also providing reliable predictions. The results from the developed analytical model are used to determine the power loss as well as sound pressure levels generated in the turbocharger bearings due to oil flow which can be correlated with the acoustic emissions of turbochargers.
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Reduction of Engine Sound Radiation through Optimization of Added Ribs

ESI North America-Wenlong Yang, Ricardo de Alba Alvarez
  • Technical Paper
  • 2020-01-0404
To be published on 2020-04-14 by SAE International in United States
With stricter pass-by norms, reducing engine noise radiation is becoming more important. Adding ribs to improve stiffness is one efficient approach to achieve this goal. This paper performs the optimization of ribs which are added on the surface of an inline six-cylinder engine block. The ribs are placed orthogonally. For the optimization, optimization variables are set up to update the dimensions of the ribs in each iteration. The limits of the size changes are defined by the optimization constraints. The overall sound power radiated from the engine block surface between 500Hz and 1450Hz is chosen as the optimization objective. In each iteration, the radiated sound power is obtained by numerical analysis of a fully coupled structural-acoustic model, while the FEM (finite element method) is adopted for calculating the structural response and BEM (boundary element method) is used to compute the noise radiation from the engine block surface. To achieve the optimized design, Genetic Algorithm (GA) is taken as the optimization algorithm in the process. It is found that the optimization process successfully converges and gives…
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Experimental and Numerical Analysis of Passive Pre-Chamber Ignition with EGR and Air Dilution for Future Generation Passenger Car Engines

DEA-IRP Groupe Renault-Cedric Libert, Fano Rampanarivo, Chistou Panagiotis, Maziar Dabiri
Universitat Politecnica de Valencia-Ricardo Novella, Jose Pastor, Josep Gomez-Soriano, Ibrahim Barbery
  • Technical Paper
  • 2020-01-0238
To be published on 2020-04-14 by SAE International in United States
Nowadays the combination of strict regulations for pollutant and CO2 emissions, together with the irruption of electric vehicles in the automotive market, is arising many concerns for internal combustion engine community. For this purpose, many research efforts are being devoted to the development of a new generation of high-performance spark-ignition (SI) engines for passenger car applications. Particularly, the PC ignition concept, also known as Turbulent Jet Ignition (TJI), is the focus of several investigations for its benefits in terms of engine thermal efficiency. The passive or un-scavenged version of this ignition strategy does not require an auxiliary fuel supply inside the PC; therefore, it becomes a promising solution for passenger car applications as packaging and installation are simple and straightforward. Moreover, combining this concept with lean burn is an interesting alternative for both improving the engine efficiency and maintaining low pollutant emissions as it enables Low Temperature Combustion (LTC) which ultimately reduces NOX emissions. EGR dilution is also an attractive approach as it is compatible with the three-way catalyst for NOX control. However, previous researches…
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Mathematical Analysis of Clutch Thermal Energy during Automatic Shifting Coupled with Input Torque Truncation

Ford Motor Company-Yijing Zhang, Yuji Fujii, Rohit Hippalgaonkar, Vladimir Ivanovic
University of Zagreb-Ivan Cvok, Josko Deur, Vanja Ranogajec
  • Technical Paper
  • 2020-01-0967
To be published on 2020-04-14 by SAE International in United States
A step-ratio automatic transmission system alters torque paths through engagement and disengagement of multiple clutches. It adjusts gear ratios to efficiently run torque sources while meeting driver demand. Yet, thermal energy loss during clutch slippage is one of the contributors to the fuel efficiency of a vehicle. In order to optimize drivetrain control strategy, including frequency of shifts, it is important to understand the cost of shift itself. During a power-on upshift, clutch thermal energy is primarily dissipated during inertia phase. The interaction between multiple clutches, coupled with input torque truncation, makes the decomposition of overall energy loss less obvious. This paper systematically presents the mathematical analysis of clutch thermal energy during the inertia phase of a typical single-transition gearshift. In practice, a quicker shift is generally favored, partly because the amount of energy loss is considered smaller. However, the analysis reveals that there is a critical input torque truncation level, as a function of transmission output torque, where a shorter shift actually results in a larger energy penalty. Numerical simulations of gear shifting as…
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Numerical Analysis of Flow around an Isolated Rotating Wheel Using a Sliding Mesh Technique

Chip Ganassi Racing-Chen Fu
University of North Carolina-Adit Sunil Misar, Mesbah Uddin, Austin Robinson
  • Technical Paper
  • 2020-01-0675
To be published on 2020-04-14 by SAE International in United States
Tire aerodynamics has long been viewed as a critical area in the ongoing research on vehicle drag reduction as it is a significant contributor to the overall automotive parasitic drag. Previous wind-tunnel experiments have revealed that the flow over a rotating wheel is a very complex phenomenon. This complexity arises from the tire-ground contact patch, various points of flow separation due to the wheel geometry, and the effects of wheel rotation. These aspects make the numerical simulation of this type of flow rather challenging. Existing literature shows a number of ways, like sliding mesh, by which to simulate the flow over an isolated wheel, but the problem of finding an accurate yet cost-effective solution still remains elusive. The current paper attempts to investigate the different methodologies to emulate the wheel motion. In addition, the paper will address the influence of mesh parameters and solver setting dependency of the solution. The wheel used in this study is similar to one of the tires used in the experiments of Fackrell and Harvey. CFD simulation veracity will be…
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Thermal Analysis of a Magnetic Contactor in Electric Vehicle Li-Ion Battery Packs

Romeo Power Technology-Gautam Pulugundla, Karlo Galvan, Prahit Dubey
  • Technical Paper
  • 2020-01-1345
To be published on 2020-04-14 by SAE International in United States
In this paper, we perform 3D numerical simulations to understand the thermal operation of a high-current-load DC Magnetic Contactor (MC) within a Li-ion battery pack. The main focus is on evaluating the thermal behavior of an electronically controlled MC through a parametric study that investigates the effect of the magnitude of electric current with the corresponding Ohmic heat generation of the MC. For the numerical analysis we perform time-accurate, conjugate heat transfer-based 3D CFD simulations on high spatial resolution grids with commercial CFD software STAR-CCM+. The results of the numerical simulations with temperature dependent material properties are validated against experimental temperature measurements at various locations on the outer body of the MC. The spatial distribution of temperature, and current within the MC and its connected components are also computed for various input parameter values to evaluate a range of its operational validity within an automotive Li-ion battery pack.
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Latticed Crane Boom Systems - Analytical Procedure

Cranes and Lifting Devices Committee
  • Ground Vehicle Standard
  • J1093_202001
  • Current
Published 2020-01-15 by SAE International in United States
This SAE information report applies to wire rope supported, latticed crane boom systems mounted on mobile construction type cranes for lift crane service.
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A Study and Mathematical Analysis of Thermionic Energy Conversion Materials Based on Their Solid State Emission Properties

BSDU-Kantaprasad Kodihal, Ankur Sagar
Published 2019-10-11 by SAE International in United States
The physical mechanism of direct energy conversion technology for space applications is well known for over a century. Whereas thermionic energy conversion is now being explored for automotive regeneration applications considering its high conversion efficiency. The thermionic emission used in space applications has operating temperatures >20000C which is much higher than available temperature at terrestrial automotive applications. Hence the key research interests are focused towards effective utilization of thermionic energy conversion for automotive waste heat recovery at considerably lower temperatures i.e. <10000C. This strongly needs a selection of suitable materials in thermionic convertor. This work shows a comprehensive study on materials and their work function for thermionic emission at relatively lower temperature. The selection of different emitter materials is based on simulation applying Richardson Dushman equation and child’s law at operating temperature ranges. The paper concludes with a comparative analysis of high and low work function materials showing their behavior of thermionic emission at specified temperature.
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Passenger Car Side Door Latch Systems

Motor Vehicle Council
  • Ground Vehicle Standard
  • J839_201910
  • Current
Published 2019-10-09 by SAE International in United States
This SAE Recommended Practice establishes minimum performance requirements and test procedures for evaluating and testing passenger car side door latch systems. It is limited to tests that can be conducted on uniform test fixtures and equipment in commercially available laboratory test facilities. The test procedures and minimum performance requirements outlined in this document are based on currently available engineering data. It is intended that all portions of the document will be periodically reviewed and revised, as additional knowledge regarding vehicle latch performance under impact conditions is developed.
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