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Numerical Study of the Maximum Impact on Engine Efficiency When Insulating the Engine Exhaust Manifold and Ports During Steady and Transient Conditions

Universitat Politècnica de València-Alberto Broatch, Pablo Olmeda, Jaime Martin, Amin Dreif
  • Technical Paper
  • 2020-37-0002
To be published on 2020-06-23 by SAE International in United States
In the present work, a study about the impact on engine performance, fuel consumption and turbine inlet and outlet temperatures adding thermal insulation to the exhaust ports, manifold and pipes before the turbocharger of a 1.6L Diesel engine is presented. First, a 0D/1D model of the engine was developed and thoroughly validated by means of an extensive testing campaign. The validation was performed by means of steady state or transient running conditions and in two different room temperatures: 20ºC and -7ºC d. Once the validation was complete, in order to quantify the significance of adding thermal isolations, the simulations were performed setting the exhaust air path before the turbine as adiabatic. This is evaluated the maximum gain of the technology. Results showed that the thermal insulation proved to have a great potential in regard to T4 increase since this would reduce the warm up time of the aftertreatment systems. However, its impact on engine efficiency was limited in both steady and transient conditions.
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A Numerical Investigation on VVA Influence on the Combustion Phase for Premixed Combustion Engine Under Partial Load Conditions

DMMM - Politecnico di Bari-Sergio Camporeale
DMMM - Politecnico di Bari, GNFM INDAM-Francesco Fornarelli
  • Technical Paper
  • 2020-37-0005
To be published on 2020-06-23 by SAE International in United States
Nowadays, the vehicle hybridization and the use of more clean fuel in heavy-duty applications brings to a new beginning in the use of spark ignition engine. In standard intake system, the pre-mixed fuel air mixture is controlled by the injection of fuel after the throttle valve. Then, intake system, consisting in intake duct, valve number and geometry and cylinder head shape influence the characteristics of the intake flow within the cylinder up to the ignition of the combustion by the spark plug. The technology advancement in fluid-power and electrical actuation gives the opportunity to decouple the intake and exhaust valve actuation with respect to the standard cam shaft distribution. The Variable Valve Actuation (VVA) concepts is not new, but its application is now affordable and flexible enough to be applied in partial load conditions. Here, by means of three-dimensional numerical simulations the intake and combustion process is studied with a finite volume approach to solve the mass, momentum and energy equations together with an Extended Coherent Flamelet Model (ECFM). Two different approaches in driving the…
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High Speed Camera Based 3D Experimental Modal Analysis

University of Ljubljana-Domen Gorjup, Janko Slavic, Miha Boltezar
  • Technical Paper
  • 2020-01-1569
To be published on 2020-06-03 by SAE International in United States
High-speed camera systems in vibration measurements are typically limited to identifying motion perpendicular to the optical axis. Depth information, lost in the imaging process, can be recovered by using the recently introduced frequency domain triangulation and consequently full 3D deflection shapes can be obtained. This research presents the required theoretical background where the multiview image data is used for spatial small harmonic motion identification. Vibrations of an arbitrary-shaped specimen can be identified in the frequency domain using only a single, moving high-speed camera, extending the field-of-view of the established image-based vibration measurement methods. Real test cases are also presented.
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Vehicle Interior Sound Quality Dynamic Objective Evaluation Inidex Analysis

Jilin University-Xiaolin Cao, Jiankun Yuan, Si Sun, Jing Chen
Jilin University Automotive Engrg Colleg-Dengfeng Wang
  • Technical Paper
  • 2020-01-1544
To be published on 2020-06-03 by SAE International in United States
The studies pertaining to vehicle interior sound quality have been gaining popularity in the last couple of decades. The vehicle subjective assessment and objective measurement are two hot research spots of this research field. For the objective evaluation, the traditional indexes that most researches used were based on a short time stationary assumption. However, when the vehicle is running, the interior sound environment is a dynamic processing. It is inconsistent with the assumption obviously. In this paper, the standard deviation and the range of several traditional psychoacoustic indexes were introduced as dynamic objective evaluation indexes to reflect the volatility and fluctuation range of these indexes. In order to evaluate the effectiveness of these dynamic objective evaluation indexes, some subjective evaluation indexes were chosen as reference parameters. Then we compared the importance degrees between the proposed dynamic objective indexes and some traditional objective evaluation indexes to the reference parameters based on the rough set theory. After the analysis, ranks of importance degree were obtained. The results are helpful to find suitable dynamic objective indexes as necessary…
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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.
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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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Suggestive Sound Design Based on Virtual Gears

IPEK - Institute of Product Engineering-Manuel Petersen, Matthias Behrendt, Leonard Heizmann, Albert Albers
  • Technical Paper
  • 2020-01-1543
To be published on 2020-06-03 by SAE International in United States
With the electrification of vehicles, new questions and problems are rising in the field of NVH. The in-cabin noises were reduced significantly due to the new drive system, but even more so the spectral composition of this noise. While the reduction of the in-cabin Sound pressure levels is generally welcomed by customers and engineers alike, the predominantly high-pitched tonal sounds of the electrical drives are normally perceived with less enthusiasm. Active sound design can help both in masking those noises, and at the least embed them in new harmonic contexts so their annoyance can be reduced. Furthermore, an active sound design can bring back the emotionality that an electrical drive is lacking compared to a classic internal combustion engine. Our hypothesis is, that if certain sounds induce specific emotions in drivers, and as a variety of research in the field of traffic psychology shows, emotions can alter the driving behavior, a specifically designed active sound design could be used to influence said behavior. We aim to make the changes in the sound sufficiently subtle, so…
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Measurement Location Optimization of Component TPA Method for Road Noise

Applus + Idiada Spain-Onno de Boer, Javier Iturbe
Applus Idiada-Beatriz Bragado Pérez
  • Technical Paper
  • 2020-01-1581
To be published on 2020-06-03 by SAE International in United States
In this paper, an investigation on the application of a non-intrusive on-site component Transfer Path Analysis (TPA) method is presented together with the comparison with a previously performed direct blocked forces method. The latter is the more common method to determine interface forces between active and passive parts of an assembly. Force transducers are placed between the investigated structure and a rigid measurement rig. The presented comparison shows an investigated whether the faster and cheaper TPA method was able to produce relevant results. The TPA method used in this work calculated the force component contributions, without disassembly of the interfaces, through the local stiffness of multiple indicator positions per interface combined with operational measurement. The method is based on the application of an inverse-matrix model. This approach was applied to a vehicle road noise investigation carried out on a roller bench at three different roller speeds. A rough surface single axle roller bench in the same conditions as for the blocked forces method was used. The matrix inversion was carried out by using an overdetermined…
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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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Linking Body-In-White and Trimmed Body Dynamic Characteristics in view of Body-In-White Mode Shape Target Setting

Siemens Digital Industries Software-Marc Brughmans, Stefano Orlando
  • Technical Paper
  • 2020-01-1553
To be published on 2020-06-03 by SAE International in United States
Target setting at Body-In-White (BIW) level is typically done for natural frequencies of global modes. Target values are commonly set based on experience or from benchmark studies with competitor vehicles. A link between these targets at BIW level and the vibro-acoustic targets at Trimmed Body (TB) level is not yet well established. Therefore, it is not always guaranteed that the TB targets will be met when the targets at BIW level are reached. Also, the other way around, not reaching a frequency target for a certain BIW mode does not necessarily imply that TB targets will not be met. Hence, there is a clear need for getting more insights in the relation between BIW dynamic properties and TB vibration behavior. In this paper techniques will be presented that establish the link between BIW and TB dynamic behavior. In addition, a large DOE campaign has been carried out to further link these dynamic properties to specific areas in the body design. Key elements in this paper are the introduction of a novel modal reduction method to…