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Viewing 1 to 30 of 39456
Technical Paper
2014-09-15
Kai Chen
The synthetic paraffinic kerosine (SPK) produced via HEFAs is of great interest for civil aviation industry as it exhibits an excellent thermal oxidative stability with significantly lower particulate matter emission. However, due to its aromatic free characteristics, the widespread use of SPK is limited by its compatibility with non-metal materials such as fuel tank elastomers. In this research the compatibility of SPK and its blends with widely used aircraft fuel tank elastomers were systematically studied. Experimental results demonstrated the volume swellability of all selected materials showed a linear relationship with volume percentage of No.3 jet fuel in SPK blend. The increase of volume percentage of No.3 jet fuel in the SPK blend increased volume swellability for all materials except fluorosilicone gasket. The alkyl benzenes and naphthalenes in the blend acted as the hydrogen donors, which facilitated the formation of polymer matrix and led to the increase of the distance between polymer chains.
Technical Paper
2014-05-20
Y. Gene Liao, Molly O'Malley, Allen Quail
Fuel consumption reduction on medium-duty tactical truck has and continues to be a significant initiative for the U.S. Army. The Crankshaft-Integrated-Starter-Generator (C-ISG) is one of the parallel hybrid propulsions to improve the fuel economy. The C-ISG configuration is attractive because one electric machine can be used to propel the vehicle, to start the engine, and to be function as a generator. The C-ISG has been implemented in one M1083A1 5-ton tactical cargo truck. This paper presents the experimental assessments of the C-ISG hybrid truck characteristics. The experimental assessments include all electric range for on- and off-road mission cycles and fuel consumption for the high voltage battery charging. Stationary tests related to the charging profile of the battery pack and the silent watch time duration is also conducted.
Technical Paper
2014-05-09
John O. Manyala, Todd W. Fritz
Electro-hydraulic actuated systems are widely used in industrial applications due to high torque density, higher speeds and wide bandwidth operation. However, the complexities and the parametric uncertainties of the hydraulic actuated systems pose challenges in establishing analytical mathematical models. Unlike electro-mechanical and pneumatic systems, the nonlinear dynamics due to dead band, hysteresis, nonlinear pressure flow relations, leakages and friction affects the pressure sensitivity and flow gain by altering the system's transient response, which can introduce asymmetric oscillatory behavior and a lag in the system response. The parametric uncertainties make it imperative to have condition monitoring with in-built diagnostics capability. Timely faults detection and isolation can help mitigate catastrophic failures. This paper presents a signal-based fault diagnostic scheme for a gearbox hydraulic actuator leakage detection using the wavelet transform. The novelty of the work is the development of a high fidelity leakage fault detection as low as 0.128 lit/min.
Technical Paper
2014-05-09
Byeong wook Jeon, Sang-Hwan Kim
This study was conducted to develop and validate a multidimensional measure of shift quality as perceived by drivers during kick-down shift events for automatic transmission vehicles. As part of the first study, a survey was conducted among common drivers to identify primary factors used to describe subjective gear-shifting qualities. A factor analysis on the survey data revealed four semantic subdimensions. These subdimensions include responsiveness, smoothness, unperceivable, and strength. Based on the four descriptive terms, a measure with semantic scales on each subdimension was developed and used in an experiment as the second study. Twelve participants drove and evaluated five vehicles with different gear shifting patterns. Participants were asked to make kick-down events with two different driving intentions (mild vs. sporty) across three different speeds on actual roadway (local streets and highway). After each event, participants were asked to complete the rating of the four descriptive terms as well as a comprehensive rating on the gear-shifting event.
Technical Paper
2014-05-09
David Lennström, Roger Johnsson, Anders Agren, Arne Nykänen
In the vehicle development process, targets are defined to fulfill customers' expectations on acoustic comfort. The interior complete vehicle acoustic targets can be cascaded down to system and component targets, e.g. insulation properties and source strengths. The acoustic transfer functions (ATFs) from components radiating airborne noise play a central role for the interior sound pressure levels. For hybrid vehicles fitted with an electric traction motor, the contribution of high frequency tonal components radiated from the motor housing needs to be controlled. The interior sound pressure due to an airborne motor order can be estimated by surface velocities and ATFs. This study addresses the ATFs measured from a large number of positions located around an electric rear axle drive (ERAD) and their influence on estimated interior noise. First, the magnitude variation between the individual ATFs and how it clearly can be visualized was presented. Displaying all ATFs in a color map revealed the magnitude at each geometrical location of the respective microphone.
Technical Paper
2014-04-15
Rakesh Kumar Maurya, Avinash Kumar Agarwal
Homogeneous charge compression ignition (HCCI) engines are attracting attention as next-generation internal combustion engines mainly because of very low NOx and PM emission potential and excellent thermal efficiency. Particulate emissions from HCCI engines have been usually considered negligible however recent studies suggest that PM number emissions from HCCI engines cannot be neglected. This study is therefore conducted on a modified four cylinder diesel engine to investigate this aspect of HCCI technology. One cylinder of the engine is modified to operate in HCCI mode for the experiments and port fuel injection technique is used for preparing homogenous charge in this cylinder. Experiments are conducted at 1200 and 2400 rpm engine speeds using gasoline, ethanol, methanol and butanol fuels. A partial flow dilution tunnel was employed to measure the mass of the particulates emitted on a pre-conditioned filter paper. The collected particulate matter (PM) was subjected to chemical analyses in order to assess the amount of Benzene Soluble Organic Fraction (BSOF) and trace metals (marker of toxicity) using Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES).
Technical Paper
2014-04-15
Amit Shrestha, Ziliang Zheng, Tamer Badawy, Naeim Henein, Peter Schihl
This paper presents a new approach for the development of six different JP-8 surrogates for application in diesel cycle simulation. The approach involves a step-wise formulation of 2-, 3-, and 4-component surrogates from a list of pure compounds which are selected based on several criteria. A MATLAB code is developed and is used in conjunction with the Ignition Quality Tester (IQT) and HYSYS software in order to formulate optimal surrogates. The first part of the results shows a comparison between the calculated and the measured DCNs for six surrogates. The differences in the properties such as the density, volatility, lower heating value, H/C ratio, molecular weight, and threshold sooting index of the surrogates and the JP-8 are also highlighted. This is followed by the evaluation of the surrogates with respect to the target JP-8 fuel. The evaluation is made in terms of ignition delays and the rate of heat release at three different IQT test temperatures. Finally, the test results are examined to evaluate the validity of the development approach and the potential use of the IQT in the development and validation of the JP-8 surrogates for application in diesel engines.
Technical Paper
2014-04-01
Robert Golimbioschi, Giampiero Mastinu, Luca Cordioli, Massimiliano Gobbi, Davide Tagliabue, Giorgio Previati, Francesco Braga
Abstract A new electric powertrain and axle for light/medium trucks is presented. The indoor testing and the simulation of the dynamic behavior are performed. The powertrain and axle has been produced by Streparava and tested at the Laboratory for the Safety of Transport of the Politecnico di Milano. The tests were aimed at defining the multi-physics perfomance of the powertrain and axle (efficiency, acceleration and braking, temperature and NVH). The whole system for indoor tests was composed by the powertrain and axle (electric motor, driveline, suspensions, wheels) and by the test rig (drums, driveline and electric motor). The (driving) axle was positioned on a couple of drums, and the drums provided the proper torques to the wheels to reproduce acceleration and braking. Additionally a cleat fixed on one drum excited the vibration of the suspensions and allowed assessing NVH performance. The simulations were based on a special co-simulation between 1D-AMESIM and VIRTUAL.LAB. The contact between the wheels and the drums of the test rig were simulated by means of VIRTUAL.LAB.
Technical Paper
2014-04-01
Ali Kolivand
Abstract Spherical involute surface topography for straight bevel gears including surface coordinates and normals are calculated. The significance of calculation of normal to the surface is mainly because it is needed for ease-off construction, tooth contact analysis and CMM measurement. The calculated surface and normals are then used to establish ease-off topography and the so-called surface of roll angle. The resultant surface of roll angle is used to allocate potential contact lines and contact ratio. The developed approach is applied to an example automotive differential straight bevel gear to calculate tooth surface, ease-off topography and surface of roll angle.
Technical Paper
2014-04-01
Joseph Y. Chen
The planetary gear train has been used as a core element for most of automatic transmissions (AT) due to its unique advantages: such as high power density, lower noise level, lower support bearing cost, and easier for mass production, compare to lay shaft or other types. In particularly, when multiple-pinion (MP) arrangement is used to accommodate flexible packaging design specifications. However, the planetary gear train does inherit a critical limit that is the lack of flexibility on gear ratio selection, because it needs to comply with certain constraints on tooth combination to meet gear train installation for assembly, load sharing for durability and phasing arrangement for noise concerns. To fully take the MP advantages for AT transmission applications, while increase the gear ratio selection was the primary motivation that prompted us to seek for some potential solutions on the MP arrangement. This report will provide the method for the proposed approach, and also reveal some of the associated assessment results.
Technical Paper
2014-04-01
Ming Chen, Dong Wang, Huiqiang Lee, Chao Jiang, Jun Xin
This paper describes the application of CAE tools in the design optimization of a DCT and driveline system of a passenger vehicle, with emphasis on NVH performance. The multi-body dynamics simulation tools are employed for driveline system analysis. The MBD model consists of the engine, transmission, clutch, drive shafts, tires and vehicle. The wheel slip effects are considered in the calculation of shuffle frequencies. In the analysis of gear whine, the transmission housing, gears and shafts are modeled by detailed 3-D finite element models, so that the mesh stiffness of the gears and the housing support stiffness are described more accurately. The calculated velocity spectra of the housing are presented. The prediction of gear rattle in the transmission is carried out. The loose gear acceleration index and the averaged impact power of free gears are calculated to assess the rattle generation potential and the level of rattle severity. The influence of the clutch spring rate and the gear backlash on rattle behavior is investigated.
Technical Paper
2014-04-01
Shawn Hawkins, Alan Holmes, David Ames, Khwaja Rahman, Rodney Malone
The General Motors (GM) 1ET35 drive unit is designed for an optimum combination of efficiency, performance, reliability, and cost as part of the propulsion system for the 2014 Chevrolet Spark Electric Vehicle (EV) [1]. The 1ET35 drive unit is a coaxial transaxle arrangement which includes a permanent-magnet (PM) electric motor and a low loss single-planetary transmission and is the sole source of propulsion for the battery-only electric vehicle (BEV) Spark. The 1ET35 is designed with experience gained from the first modern production BEV, the 1996 GM EV1. This paper describes the design optimization and development of the 1ET35 and its electric motor that will be made in the United States by GM. The high torque density electric motor design is based on high-energy permanent magnets that were originally developed by GM in connection with the EV1 and GM bar-wound stator technology introduced in the 2Mode Hybrid electric transmission, used in the Chevrolet Volt and in GM eAssist systems.
Technical Paper
2014-04-01
Zhang Yan, Liu Zhien, Xiaomin Wang, Hao Zheng, Yu Xu
For fracture cracks that occurred in the tight coupling exhaust manifold durability test of a four-cylinder gasoline engine with EGR channel, causes and solutions for fracture failure were found with the help of CFD and FEA numerical simulations. Wall temperature and heat transfer coefficient of the exhaust manifold inside wall were first accurately obtained through the thermal-fluid coupling analysis, then thermal modal and thermoplastic analysis were acquired by using the finite element method, on account of the bolt pretightening force and the contact relationship between flange face and cylinder head. Results showed that the first-order natural frequency did not meet the design requirements, which was the main reason of fatigue fracture. However, when the first-order natural frequency was rising, the delta equivalent plastic strain was increasing quickly as well. Ultimately, to solve the problem, the semi-shell was strengthened and some dents of critical areas were added so as to absorb some energy, consequently, the plastic strain decreased in the process of thermal expansion and cooling contraction.
Technical Paper
2014-04-01
Liu Zhien, Xiaomin Wang, Zhang Yan, Xueni Li, Yu Xu
In order to predict the thermal fatigue life of the internal combustion engine exhaust manifold effectively, it was necessary to accurately obtain the unsteady heat transfer process between hot streams and exhaust manifold all the time. This paper began with the establishment of unsteady coupled heat transfer model by using serial coupling method of CFD and FEA numerical simulations, then the bidirectional thermal coupling analysis between fluid and structure was realized, as a result, the difficulty that the transient thermal boundary conditions were applied to the solid boundary was solved. What's more, the specific coupling mode, the physical quantities delivery method on the coupling interface and the surface mesh match were studied. On this basis, the differences between strong coupling method and portioned treatment for solving steady thermal stress numerical analysis were compared, and a more convenient and rapid method for solving static thermal stress was found. Finally, aiming at the thermal stress analysis of steady and unsteady temperature fields, the thermal fatigue life of the exhaust manifold was estimated in application of Manson-Coffin formula, giving a general qualitative analysis.
Technical Paper
2014-04-01
Vaheed Nezhadali, Martin Sivertsson, Lars Eriksson
The importance of including turbocharger dynamics in diesel engine models are studied, especially when optimization techniques are to be used to derive the optimal controls. This is done for two applications of diesel engines where in the first application, a diesel engine in wheel loader powertrain interacts with other subsystems to perform a loading operation and engine speed is dictated by the wheel speed, while in the second application, the engine operates in a diesel-electric powertrain as a separate system and the engine speed remains a free variable. In both applications, mean value engine models of different complexities are used while the rest of system components are modeled with the aim of control study. Optimal control problems are formulated, solved, and results are analyzed for various engine loading scenarios in the two applications with and without turbocharger dynamics. It is shown that depending on the engine loading transients, fuel consumption and operation time can widely vary when the turbocharger dynamics are considered in the diesel engine model.
Technical Paper
2014-04-01
Robert Cloudt
A particulate matter On-Board Diagnostics method based on temperature sensing is demonstrated. The concept applies a detection filter downstream of the main particulate filter and a flow diversion pipe. A small fraction of the main exhaust flow is diverted through the detection filter. In case the main soot filter has some leakage, soot will collect on the detection filter where it reduces the filter's permeability. As a result the diverted flow is reduced. This effect is sensed by a temperature sensor placed downstream of the detection filter because the change of diverted mass flow results in a change of heating rate. This principle allows particulate filter diagnostics based on cost-effective and readily available sensing technology. Comprehensive diagnostics software is developed to interpret and assess the temperature signal. The developed diagnostics software detects particulate filter filtration inefficiency and performs plausibility checks. The concept is demonstrated using an instrumented test vehicle with purposely damaged particulate filter.
Technical Paper
2014-04-01
Kambiz Jahani, Sajjad Beigmoradi
The efficiency of the vehicle cooling system strongly depends on the air flow through the radiator core. The flow through the radiator core in turn depends on other panels that are in the vicinity of the radiator. In this study, the effect of geometrical change at vehicle front-end including the whole bonnet, grille and bumper area is investigated by means of Computational Fluid Dynamics (CFD). Numerical modeling is carried out by means of CAE tools. Simulations are performed for maximum power and maximum torque conditions, monitoring the mass flow rate through the radiator core and velocity contribution over the radiator face. To the velocity field of the airflow, the heat exchangers are represented as porous media and fan module is modeled utilizing Multiple Reference Frame (MRF) approach. The validity of the developed simulation capability is tested by successful comparison with the available experimental data for the base model at the given operating conditions. On studying the model with complete new front-end style, local modifications are applied incorporating adding airguide, flap and anti-recycler in order to enhance the flow distribution in the vicinity of radiator and increase the mass flow rate passing through it.
Technical Paper
2014-04-01
Kesav Kumar Sridharan, Ravish Masti, Ravi Kumar, Jiancheng Xin, Wendong Wang, Henry Kong
Abstract In hybrid electric vehicles (HEVs) and full electric vehicles (EVs), efficient electrical power management with proper supply of power at the required voltage levels is essential. A DC (Direct Current)-DC converter is one of the key electrical units in a HEV/EV. The DC-DC converter dealt in the present work is intended to create the DC voltages necessary to power the accessories. The electronic circuit in this DC-DC converter consists of high power devices like Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs), inductors, transformers, etc. mounted on a printed circuit board (PCB). The DC-DC converter interacts with a high voltage battery pack and supplies a low voltage power to the accessory battery. Due to this power handling operation, the devices in the convertor experience high temperatures. The temperature rise of the devices beyond the permissible limits could be detrimental to an efficient and safe operation of the converter. This paper deals with a robust and optimal thermal design of an air-cooled DC-DC Converter in order that the temperature (primary design parameter) of each of the devices is at a minimum and below the corresponding permissible limit of the device.
Technical Paper
2014-04-01
Felix Regin A, Abhinav Agarwal, Niraj Kumar Mishra
Abstract Increased engine thermal load, front end styling and compact vehicle requirements have led to significant challenges for vehicle front end designer to provide innovative thermal management solutions. The front end cooling module design which consists of condenser, radiator, fan and intercooler is an important part of design as it ensures adequate heat removal capacity of radiator over a wide range of operating conditions to prevent overheating of engine. The present study describes the optimization of cooling air flow opening in the front end using CFD methodology of a typical passenger car. The predicted vehicle system resistance curve and coolant inlet temperature to the radiator are used for the selection of cooling modules and to further optimize the front end cooling opening area. This leds to the successful optimization of the front end, selection of cooling modules with significant cost savings by reducing prototype testing and design cycle time.
Technical Paper
2014-04-01
Chengyu Zhang, Ge-Qun Shu, Hua Tian, Haiqiao Wei, Guopeng Yu, Youcai Liang
Abstract This paper presents a model system TEG-DORC that employs thermoelectric generator (TEG) as a topping cycle integrated with a dual-loop organic Rankine bottoming cycle (DORC) to recover exhaust heat of internal combustion engine (ICE). The thermodynamic performance of TEG-DORC system is analyzed based on the first and second law of thermodynamics when system net output power Wnet, thermal efficiency ηth, exergy efficiency ηe and volumetric expansion ratio are chosen as objective functions. The model has many parameters that affect combined system performance such as TEG scale, evaporation pressure of high temperature ORC loop (HT loop) Pevp,HT, condensation temperature of HT loop Tcond,HT. It is suggested that HT loop has a vital influence on system performance. The results show that TEG-DORC system can significantly improve system performance, and system net output power gets maximum (30.69kW) when Tcond,HT is 370K and Pevp,HT is 4MPa, accordingly, the absolute effective thermal efficiency increases by 5.2%.
Technical Paper
2014-04-01
Hiroki Tanaka, Shunsuke Somezawa, Takahiro Sako, Yasuyuki Sakai, Hiromitsu Ando, Kazunari Kuwahara
A fuel design concept for an HCCI engine based on chemical kinetics to optimize the heat release profile and achieve robust ignition was proposed, and applied to the design of the optimal methane-based blend. Ignition process chemistry of each single-component of natural gas, methane, ethane, propane, n-butane and isobutane, was analyzed using detailed chemical kinetic computations. Ethane exhibits low ignitability, close to that of methane, when the initial temperature is below 800 K, but higher ignitability, close to those of propane, n-butane and isobutane, when the initial temperature is above 1100 K. Furthermore, ethane shows a higher heat release rate during the late stage of the ignition process. If the early stage of an ignition process takes place during the compression stroke, this kind of heat release profile is desirable in an HCCI engine to reduce cycle-to-cycle variation during the expansion stroke. According to results from engine operation tests using dual-component fuels with methane as the primary component and ethane, propane, n-butane and isobutane as the secondary component, methane/ethane shows a lower COV of IMEP when CA50 is set at the same timing for the expansion stroke.
Technical Paper
2014-04-01
Markus Schwaderlapp, Mirko Plettenberg, Dean Tomazic, Gregor Schuermann, Felix Ring, Stephen Bowyer
Measures for reducing engine friction within the powertrain are assessed in this paper. The included measures work in combination with several new technologies such as new combustion technologies, downsizing and alternative fuels. The friction reduction measures are discussed for a typical gasoline vehicle. If powertrain friction could be eliminated completely, a reduction of 15% in CO2 emissions could be achieved. In order to comply with more demanding CO2 legislations, new technologies have to be considered to meet these targets. The additional cost for friction reduction measures are often lower than those of other new technologies. Therefore, these measures are worth following up in detail.
Technical Paper
2014-04-01
Vinay Ranganath, Nitin Bhiwapurkar, Haresh Bhere
Abstract Induction motor is very much used in mild hybrid vehicles because of its low cost, rugged structure and reliability. To test the induction motor controller in hardware-in-the-loop (HIL) simulation environment efficiently in both motoring and generating modes, generally, an instantaneous dynamic model of induction motor drive is used which requires the instantaneous values of PWM signals of inverter switches and hence a very high sampling frequency of about twenty times the switching frequency is required to effectively capture all the switching information of MOSFETS. This requires a HIL system with very powerful processor which increases the overall cost of system. In this paper, a dynamic average-value model of induction motor drive is developed in MATLAB/Simulink which requires only the duty cycle information instead of instantaneous switching information of PWM signals. Its performance is compared with the instantaneous model which is also developed in MATLAB/Simulink. At different operating conditions, it is shown that the waveforms of motor torque, phase current etc. of average-value motor drive model trace those of instantaneous model even if the sampling frequency of average-value model (10 kHz) is twenty times lesser than that of instantaneous model (200 kHz) for the PWM switching frequency of 10 kHz.
Technical Paper
2014-04-01
Junji Ando, Takuya Tsuda, Hiroyuki Ando, Yoshihiro Niikawa, Kunihiko Suzuki
This paper describes the development of the new third-generation electronically controlled all-wheel drive (AWD) coupling that achieves drastically improved drag torque performance and torque accuracy at low temperatures, and contributes to higher fuel efficiency through weight reduction in the driveline. One issue for electronically controlled AWD couplings is an increase in torque due to higher lubricant viscosity at low temperatures, especially below 0°C, because of clutch slide with the lubricant sealed inside the couplings. The developed third-generation electronically controlled AWD coupling addresses this issue by focusing on the surface texture of the electromagnetic clutch. The third-generation coupling also restricts the torque increase by actively utilizing the dynamic pressure between the clutch plates and increasing the clearance of the clutch plates at low temperatures where viscosity increases. This enables further weight reduction in the driveline. In order to reduce drag torque at low temperatures, a macroscopic sliding surface profile in the order of tens of micrometers is provided on the electromagnetic clutch under fluid lubrication.
Technical Paper
2014-04-01
Mathieu Picard, Camille Baelden, Tian Tian, Takayuki Nishino, Eiji Arai, Hiroyuki Hidaka
The rotary engine provides high power density compared to piston engine, but one of its downside is higher oil consumption. A model of the oil seals is developed to calculate internal oil consumption (oil leakage from the crankcase through the oil seals) as a function of engine geometry and operating conditions. The deformation of the oil seals trying to conform to housing distortion is calculated to balance spring force, O-ring and groove friction, and asperity contact and hydrodynamic pressure at the interface. A control volume approach is used to track the oil over a cycle on the seals, the rotor and the housing as the seals are moving following the eccentric rotation of the rotor. The dominant cause of internal oil consumption is the non-conformability of the oil seals to the housing distortion generating net outward scraping, particularly next to the intake and exhaust port where the housing distortion valleys are deep and narrow. Simulation with housing transverse waviness shows that increasing spring force can lead to an unexpected increase in internal oil consumption.
Technical Paper
2014-04-01
Karthikeyan N, Anish Gokhale, Narendra Bansode
Abstract The Continuous Variable Transmission (CVT) in scooters is used to transmit the power from the engine to the wheels. The CVT transmission consists of a drive pulley and a driven pulley connected to each other through a belt. The centrifugal clutch is attached to the rear pulley which transmits the power to the wheel. The engagement and disengagement of the clutch generates heat and friction heat is generated between the belt and pulley, thereby requiring continuous external cooling for its safe operation. A centrifugal fan is employed for cooling of the CVT belt. Since the cooling fan takes air from atmosphere, there is always a possibility of dust from the atmosphere entering the system, which might cause wear of pulley and belt, thereby decreasing the performance of the transmission system. The objective of the work is to analyze the dust ingress pattern in to CVT housing. The work aims at simulating the possible conditions for dust entry into the CVT housing for a complete scooter and the study of different design proposals to minimize the dust entry without compromising the cooling requirement of CVT.
Technical Paper
2014-04-01
Rok Kopun, Dongsheng Zhang, Wilfried Edelbauer, Bernhard Stauder, Branislav Basara, David Greif
In this paper, a recently improved Computational Fluid Dynamics (CFD) methodology for virtual prototyping of the heat treatment of cast aluminum parts, above most of cylinder heads of internal combustion engines (ICE), is presented. The comparison between measurement data and numerical results has been carried out to simulate the real time immersion quenching cooling process of realistic cylinder head structure using the commercial CFD code AVL FIRE®. The Eulerian multi-fluid modeling approach is used to handle the boiling flow and the heat transfer between the heated structure and the sub-cooled liquid. While for the fluid region governing equations are solved for each phase separately, only the energy equation is solved in the solid region. Heat transfer coefficients depend on the boiling regimes which are separated by the Leidenfrost temperature. The objective of the present research work is to present an update of the quenching model where instead of constant, variable Leidenfrost temperature is applied.
Technical Paper
2014-04-01
Marco Barbolini
The air filters in an air intake system permanently remove foreign particles such as dust, dirt and soot from the intake air, thereby maintaining the performance of the engine and protecting it from damage. The filter performance is typically a trade-off between pressure loss, load capacity and efficiency. Exhaust gas regulations and customer requirements such as filter duration always determine air filter development. For this reason Röchling Automotive has developed a new software tool for estimating air filter lifetime which simplifies and significantly shortens the pre-development of filter elements with regard to filtration and pressure drop. In addition, it is possible to compare the different filter geometries (number of pleats, height, paper etc.) in order to limit the number of different filter elements, for example for a complete series of cars. By correlating the total air consumption with the average dust concentration typical for the environment involved, the air filter lifetime can be precisely predicted.
Technical Paper
2014-04-01
Vishank Kumar, Dimitry Sediako, Lukas Bichler
The demand for light weight vehicles continues to stimulate extensive research into the development of light weight casting alloys and optimization of their manufacturing processes. Of primary relevance are Aluminum (Al) and Magnesium (Mg) based alloys, which have successfully replaced selected iron based castings in automobiles. However, optimization of as-cast microstructure, processing and performance remains a challenge for some Al-based alloys. In this context, placement of chills in castings has been frequently used to locally manipulate the solidification conditions and microstructure of a casting. In this work, the effect of using an active copper chill on the residual strain profile of a sand-cast B319 aluminum alloy was investigated. Wedge-shaped castings were produced with three different cooling conditions: copper plate chill, copper pipe with cooling water and no chill (baseline). The effect of chill condition on the variation of residual strain in the casting was investigated using neutron diffraction approach.
Technical Paper
2014-04-01
Philipp von Hartrott, Thomas Seifert, Steven Dropps
HiSiMo cast irons are frequently used as material for high temperature components in engines as e.g. exhaust manifolds and turbo chargers. These components must withstand severe cyclic mechanical and thermal loads throughout their service life. The combination of thermal transients with mechanical load cycles results in a complex evolution of damage, leading to thermomechanical fatigue (TMF) of the material and, after a certain number of loading cycles, to failure of the component. In this paper (Part I), the low-cycle fatigue (LCF) and TMF properties of HiSiMo are investigated in uniaxial tests and the damage mechanisms are addressed. On the basis of the experimental results a fatigue life model is developed which is based on elastic, plastic and creep fracture mechanics results of short cracks, so that time and temperature dependent effects on damage are taken into account. The model can be used to estimate the fatigue life of components by means of finite-element calculations (Part II of the paper).
Viewing 1 to 30 of 39456