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Study of the Rear Declination Angle Influence on Vehicle Contamination

General Motors-Danilo Oliveira
university of campinas-Rogerio Goncalves dos Santos PhD
  • Technical Paper
  • 2020-01-0691
To be published on 2020-04-14 by SAE International in United States
This paper presents contamination simulation results of a 2004 Chevrolet Malibu Maxx with different morphed rear declination angles geometry to understand that effect on the vehicle contamination. Computational fluid dynamics highly-resolved time accurate simulations were performed using a commercial Lattice-Boltzmann solver, to compare the rear end contamination with five different rear declination angles. Aerodynamics simulations were also performed and presented good correlation with theoretical data. The contamination results were compared with aerodynamics simulation results in order to find a trend between the two areas for different declination angles.
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Computational analysis of spray pre-treatment in automotive applications

ESS Engineering Software Steyr-Muraleekrishnan Menon, Ravi Kanth Borra, Martin Schifko, Samiullah Baig
  • Technical Paper
  • 2020-01-0479
To be published on 2020-04-14 by SAE International in United States
The automotive coating industry consists of several processes targeting the reliability and longevity of the manufactured Body-In-White (BIW) with process optimization playing a key role. Pre-treatment of BIW is one of the important aspects and this involves processes in the paint shop and body-in-white shop. The relevance of cleaning every part of the BIW is well known in the industry, and we will focus on the spray wash processes. While the industry currently relies on experiences from previous designs and experimental observations from model studies, this drastically slows down process optimization for new car models. Recent developments in Computer Aided Engineering (CAE) industry has shown capability to perform reliable studies using computer models that speeds up processes. The current study focuses on the Computational Fluid Dynamic (CFD) evaluation of spray washing of a BIW using a meshless method known as Smoothed Particle Hydrodynamics (SPH). The study specifically discusses simulation of a washing process, where a car BIW is moving through pre-treatment line where, specifically arranged set of nozzles are spraying water at a constant flow…
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Investigation of the Effect of Tire Deformation on Open-Wheel Aerodynamics

Graz University of Technology-Philipp Eder, Cornelia Lex
U.A.S. Graz-Thomas Gerstorfer, Thomas Amhofer
  • Technical Paper
  • 2020-01-0546
To be published on 2020-04-14 by SAE International in United States
This paper introduces a finite element (FE) approach to determine tire deformation and its effect on open-wheeled racecar aerodynamics. In recent literature the tire deformation was measured optically using cameras during wind tunnel testing. Combined loads like accelerat-ing at corner exit are difficult to reproduce in wind tunnels and would require several camer-as to measure the tire deformation. In contrast, an FE approach is capable of determining the tire deformation in combined load states accurately and additionally provides the possibility to vary further parameters, for example, the coefficient of friction. The FE tire model was validated using stiffness measurements, contact patch measurements and steady-state cornering measurements on a flat belt tire test rig. The deformed shape of the FE model was used in a computational fluid dynamics (CFD) simulation. A sensitivity study was created to determine the effect of the tire deformation on aerodynamics for un-loaded, purely vertically loaded and combined vertical, lateral and longitudinal forces. In addition, the influence of these three tire deformations was investigated in a CFD study using a full vehicle…
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Development of the Defrost Performance Evaluation Technology in Automotive using Design Optimization Analysis Method

Hyundai Mobis-Hyeonseok Seo, Jinwon seo, Bongkeun Choi
  • Technical Paper
  • 2020-01-0155
To be published on 2020-04-14 by SAE International in United States
In this study, we developed the defrost performance evaluation technology using the multi-objective optimization method based on the CFD. The defrosting is one of the key factors to ensure the drivers’ safety using the forced flow having proper temperature from HVAC during drive. There are many factors affecting the defrost performance, but the configurations of guide-vane and discharge angles in the center DEF duct section which are main design factors of the defrost performance in automotive, so these were set to the design parameters for this study. For the shape-optimization study, the discharge mass flow rate from the HVAC which is transferred to the windshield and the discharge areas in the center DEF duct were set to the response parameters. And then, the standard deviation value of mass flow rate on the selected discharge areas checking the uniformity of discharge flow was set to the objective function to find the optimal design. The results on the windshield from optimization analysis were quantified from some kind of standards to evaluate the defrost performance, in particular, the…
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Visualization of Turbulence Anisotropy in the In-cylinder Flow of Internal Combustion Engines

Graz University of Technology-Andreas Wimmer
LEC GmbH-Rajat Soni, Clemens Gößnitzer, Gerhard Pirker
  • Technical Paper
  • 2020-01-1105
To be published on 2020-04-14 by SAE International in United States
Anisotropy is one of the most important characteristics of turbulent flows. In internal combustion engines, anisotropy significantly influences processes such as mixture formation and flame propagation. There are many different visualization strategies in the literature that make the impact of anisotropy on specific parameters more accessible for analysis. However, traditional methods are unable to display anisotropy directly in the physical domain. Instead, they use invariant maps, leading to the loss of important information. Thus, interpretation of the results becomes difficult especially when a large number of data points exist. This paper overcomes this shortcoming by visualizing turbulence anisotropy directly in the physical domain. Through the application of componentality contours, the anisotropic properties of turbulence in the three-dimensional engine geometry are directly visualized; the focus is on non-reactive flows. However, the methodology can easily be extended to reactive flows. By using an HSV (hue, saturation and value) color map, the three limiting states of turbulence (one-component, two-component and isotropic turbulence) are displayed in the three-dimensional physical domain. Thus, the assessment and interpretation of the results is…
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Effects of geometry on passive pre-chamber combustion characteristics

King Abdullah Univ of Science & Tech-Mickael Silva, Sangeeth Sanal, Ponnya Hlaing, Bengt Johansson, Hong G. Im
Saudi Aramco-Emre Cenker
  • Technical Paper
  • 2020-01-0821
To be published on 2020-04-14 by SAE International in United States
Towards a fundamental understanding of the ignition characteristics of pre-chamber (PC) combustion engines, computational fluid dynamics (CFD) simulations were conducted using CONVERGE. To assist the initial design of the KAUST pre-chamber engine experiments, the primary focus of the present study was to assess the impact of design parameters such as throat diameter, nozzle diameter, and nozzle length. The well-stirred reactor combustion model coupled with a methane oxidation mechanism reduced from GRI 3.0 was used. A homogeneous charge of methane and air with λ = 1.3 on both the PC and main chamber (MC) was assumed. The geometrical parameters were shown to affect the pre-chamber combustion characteristics, such as pressure build-up, radical formation, and heat release as well as the composition of the jets penetrating and igniting the main chamber charge. In addition, the backflow of species pushed inside the pre-chamber due to the flow reversal (FR) event was analyzed. It was found that the narrow throat type of pre-chamber is strongly influenced by the throat diameter, but weakly influence by nozzle length. A flow reversal…
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Numerical Investigation of the Combustion Kinetics of Partially Premixed Combustion (PPC) Fueled with Primary Reference Fuel

King Abdullah Univ of Science & Tech-Xinlei Liu
Tianjin University-Yuanyuan Zhao, Hu Wang, Daojian Liu, Wang chen, Hongyan Zhu, Mingfa Yao
  • Technical Paper
  • 2020-01-0554
To be published on 2020-04-14 by SAE International in United States
This work numerically investigates the detailed combustion kinetics in a gasoline compression ignition (GCI) engine using three fuel injection strategies, including single-injection, double-injection, port fuel injection and direct injection (PFI+DI). A reduced Primary Reference Fuel (PRF) chemical kinetics mechanism was coupled with CONVERGE-SAGE CFD model to predict GCI combustion under various operating conditions. To provide insight into key reaction pathways, a post-process tool was used. The validated Converge CFD code with the PRF chemistry and the post-process tool was applied to investigate how the ignition occurs during the low-to high-temperature reaction transition and how it varies due to single- and double-injection and PFI+DI injection strategies. Three characteristic GCI combustion features were selected: (1) initial low temperature heat release (LTHR); (2) intense LTHR, where both iso-octane and n-heptane were converted to intermediates through oxygen-related reactions; (3) early stage high temperature heat release (HTHR) with CH2O as the core source species. It is found that the heat release was primarily dominated by the reaction H+O2 (+M)=HO2 (+M) and AC8H¬17+O2=AC8H17O2 during LTHR. For single- and double-injection, the high…
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Engineering Applications of Multi-Dimensional CFD Analysis of Lubrication System

Cummins-Ranjit Tawar, Sanjeev Bedekar
Cummins India Ltd-Sandesh Chitnis
  • Technical Paper
  • 2020-01-1110
To be published on 2020-04-14 by SAE International in United States
This paper reports on a rigorous, transient, three-dimensional CFD analysis of the complete lubrication system of automotive internal combustion engines. The computational domain of such a model is vast and includes scores of bearings as well as components such as the pump, pressure relief valve, oil filter, oil cooler, piston cooling jets etc. Thus far, the only publication on 3D CFD analysis of a complete engine lubrication system was for a 16-cylinder engine in which the feasibility and the potential engineering opportunities of such a model were demonstrated. The timelines for setting up and running such a complex CFD model are comparable to that of a 1D model. In this paper, the following four topics will be addressed: 1. Showcase the capability of the CFD software tool to accurately, robustly and reliably predict the engine lube system performance of a wide variety of automotive engines with same set of input constants i.e. no tuning. Best analysis practices were developed in order to achieve this goal by compensating for the variabilities that arise in a complex…
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The GTU – A New Realistic Generic Pickup Truck and SUV Model

Ford Motor Company-Sudesh Woodiga, Kevin Howard, Paul Norman, Neil Lewington, Robert Carstairs, Burkhard Hupertz, Karel Chalupa
  • Technical Paper
  • 2020-01-0664
To be published on 2020-04-14 by SAE International in United States
Traditionally, ground vehicle aerodynamics has been researched with highly simplified models such as the Ahmed body and the SAE model. These models established and advanced the fundamental understanding of bluff body aerodynamics and have generated a large body of published data, however, their application to the development of passenger vehicles is limited by the highly idealized nature of their geometries. To date, limited data has been openly published on aerodynamic investigations of production vehicles, most likely due to the proprietary nature of production vehicle geometry. In 2012, Heft et al. introduced the realistic generic car model ‘DrivAer’ that better represents the flow physics associated with a typical production vehicle. The introduction of the DrivAer model has led to a broad set of published data for both physical and computational investigations and the DrivAer model has proven itself invaluable as a tool for the correlation and calibration of wind tunnels, the validation of computational fluid dynamics (CFD) codes and increasing the understanding of the fundamental flow physics around passenger vehicles. Automotive sales trends in the United…
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A direct 1D/3D (GT-SUITE/SimericsMP+) coupled computational approach to study the impact of engine oil pan sloshing on Lubrication pump performance

Gamma Technologies LLC-Rodrigo Aihara, Craig Tanouye, Jonathan Harrison
General Motors LLC-Scott GENDRON, Jeff Schlautman
  • Technical Paper
  • 2020-01-1112
To be published on 2020-04-14 by SAE International in United States
During a vehicle drive cycle the oil in the engine oil pan sloshes very vigorously due to the acceleration of the vehicle. This can cause the pickup tube in the engine oil pan to become uncovered from oil and exposed to air, which then affects the lubrication pump performance. Engine oil pan sloshing is inherently a 3D problem as the free oil surface is constantly changing. Multi-dimensional Computational Fluid Dynamics (CFD) methods are very useful to simulate such problems with high detail and accuracy but are computationally very expensive. Part of the engine lubrication system, such as the pump, can be modelled in 1D which can predict accurate results at relatively high computational speeds. By utilizing the advantages of both worlds, a coupled 1D-3D simulation approach has been developed to capture the detailed oil sloshing phenomenon in SimericsMP+ and the system level simulation is conducted in GT-SUITE where spatial data is not required. In this method, both the tools are run concurrently with the boundary conditions updated at the beginning of each time step. Experimental…