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Study of Friction Reduction Potential in Light- Duty Diesel Engines by Lightweight Crankshaft Design Coupled with Low Viscosity Oil

General Motors-Salvatore Mafrici
  • Technical Paper
  • 2020-37-0006
To be published on 2020-06-23 by SAE International in United States
Over the last two decades, engine research has been mainly focused on reducing fuel consumption in view of compliance with more stringent homologation cycles and customer expectations. As it is well known, the objective of overall engine efficiency optimization can be achieved only through the improvement of each element of the efficiency chain, of which mechanical constitutes one of the two key pillars (together with thermodynamics). In this framework, the friction reduction for each mechanical subsystem has been one of the most important topics of modern Diesel engine development. The present paper analyzes the crankshaft potential as contributor to the mechanical efficiency improvement, by investigating the synergistic impact of crankshaft design itself and oil viscosity characteristics (including new ultra-low-viscosity formulations already discussed in SAE Paper 2019-24-0056). For this purpose, a combination of theoretical and experimental tools have been used to design an extremely lightweight crankshaft and to evaluate the effects of main and conrod bearings dimensioning, clearances and oil viscosity, considering not only the impact from a friction perspective but also from a structural and…
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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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Estimation the Interior Sound Quality in BEV's Regarding Measurements on the Roller Test Bench: Focusing on Tonal Omponents

AVL Deutschland GmbH-Daniel Schecker, Eugen Deisling, Peter Uerlings
  • Technical Paper
  • 2020-01-1542
To be published on 2020-06-03 by SAE International in United States
Development of BEVs gains more and more importance for OEMs, Tier 1s and DSPs and the project volumes continue to grow steadily. Even though the complexity of electric drive trains is reduced in comparison to combustion drive lines, the requirements for NVH development increases. Masking effects of noise through combustion noise fall away, the overall noise level decreases and the high frequency noises from the electric motors, inverters and transmissions dominate the overall impression of this new technology. Because of the missing combustion noise also noises like rolling noise from tires and wind noise is felt more and more disturbing for customers and pedestrians. The NVH character of any vehicle is highly dependent on its operating condition. With BEVs, it mainly depends on the vehicle speed, torque, temperature and state of charge of the battery. For this reason customers usually want to measure many speed-ups with constant torque steps. During a 3 Year cooperation with a big OEM almost all premium BEVs on the German market were measured/benchmarked to get a feedback about the own…
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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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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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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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On Prediction of Automotive Clutch Torsional Vibrations

Theofilos Gkinis PhD
Loughborough Univ-Homer Rahnejat
  • Technical Paper
  • 2020-01-1508
To be published on 2020-06-03 by SAE International in United States
Automotive clutches are prone to rigid body torsional vibrations during engagement, a phenomenon referred to as take-up judder. This is also accompanied by fore and aft vehicle motions. Aside from driver behaviour in sudden release of clutch pedal (resulting in loss of clamp load), and type and state of friction lining material, the interfacial slip speed and contact temperature can significantly affect the propensity of clutch to judder. The ability to accurately predict the judder phenomenon relies significantly on the determination of operational frictional characteristics of the clutch lining material. This is dependent upon contact pressure, temperature and interfacial slip speed. The current study investigates the ability to predict clutch judder vibration with the degree of complexity of the torsional dynamics model. For this purpose, the results from a four and nine degrees of freedom dynamics models are compared and discussed. Subsequently, the predictions are compared with the acquired data from an automotive driveline test rig. It is shown that the complexity of the dynamic model, intended for the study of a clutch system, can…
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Installation Effects on the Flow Generated Noise From Automotive Electrical Cooling Fans

KTH CCGEx-Mikael Karlsson
Volvo Technology & Chalmers-Sassan Etemad
  • Technical Paper
  • 2020-01-1516
To be published on 2020-06-03 by SAE International in United States
With the electrification of road vehicles comes new demands on the cooling system. Not the least when it comes to noise. Less masking from the driveline and new features, as for example, cooling when charging the batteries drives the need for silent cooling fans. In this work a novel e-fan is studied in different generalized installations and operating conditions. The fans (a cluster configuration) are installed in a test rig where the operation could be controlled varying the speed, flow rate and pressure difference over the fan. On the vehicle side of the fan a generalized packaging space (similar to an engine bay for conventional vehicles) is placed. In this packaging space different obstruction can be placed to simulate the components and radiators used in the vehicle. Here generalized simple blocks in different configuration are used to provide well defined and distinct test cases. Of special interest are cases with poor inlet flow profile and the influence of this on the sound generation. The tests are currently in progress and results will be provided on…
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Effects of On-Road Conditions on HVAC Noise

Univ. Of Erlangen-Nuremberg-Andreas Logdesser, Stefan Becker
  • Technical Paper
  • 2020-01-1555
To be published on 2020-06-03 by SAE International in United States
Noise inside the passenger cabin is made up of multiple sources. A significant reduction of the major sound sources such as the engine, wind and tire noise helped to improve the comfort for passengers. As a consequence, the HVAC sound (heating, ventilation and air-conditioning) is unmasked as a primary noise source inside the passenger cabin and has to be taken into consideration when designing passenger cabin sound. While HVAC sound is often evaluated at stop, the most common situation of its use is while driving. In case of fresh air as mode of operation, the HVAC system is coupled to the environment through the air intake. Any change in the boundary conditions due to on-road driving events and gusts of wind affects the flow field in the HVAC system and in turn influences HVAC noise. This study investigates the effect of mass flow and pressure fluctuations on the HVAC noise. In a first step, major influences on the HVAC system are identified in an on-road test. For further investigation, the HVAC system is analyzed in…
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Hardware-in-the-Loop Testing of Electric Traction Drives with an Efficiency Optimized DC-DC Converter Control

RWTH Aachen University-Konstantin Etzold, René Scheer, Timm Fahrbach, Shuang Zhou, Rafael Goldbeck, Daniel Guse, Fabian Frie, Dirk Uwe Sauer, Rik W. De Doncker, Jakob Andert
  • Technical Paper
  • 2020-01-0462
To be published on 2020-04-14 by SAE International in United States
In order to reduce development cost and time, frontloading is an established methodology for automotive development programs. With this approach, particular development tasks are shifted to earlier program phases. One prerequisite for this approach is the application of Hardware-in-the-Loop test setups. Hardware-in-the-Loop methodologies have already successfully been applied to conventional as well as electrified powertrains considering various driving scenarios. Regarding driving performance and energy demand, electrified powertrains are highly dependent on the dc-link voltage. However, there is a particular shortage of studies focusing on the verification of variable dc-link voltage controls by Hardware-in-the-Loop setups. This article is intended to be a first step towards closing this gap. Thereto, a Hardware-in-the-Loop setup of a battery electric vehicle is developed. The electric powertrain consists of an interior permanent magnet synchronous machine and an inverter, which are set up as real components at a laboratory test bench. The test bench is connected to a real-time vehicle simulation including a battery model and the dc-dc converter model. The entire Hardware-in-the-Loop setup is successfully validated by vehicle measurements performed on…