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Viewing 1 to 30 of 3868
2016-10-24
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Separate sub-sessions cover zero-dimensional, one-dimensional, and quasi-dimensional models for simulation of SI and CI engines with respect to: engine breathing, boosting, and acoustics; SI combustion and emissions; CI combustion and emissions; fundamentals of engine thermodynamics; numerical modeling of gas dynamics; thermal management; mechanical and lubrication systems; system level models for controls; system level models for vehicle fuel economy and emissions predictions.
2016-05-01
Journal Article
2015-01-9148
Saeed Asgari, Shailendra Kaushik
Abstract A linear parameter varying (LPV) reduced order model (ROM) is used to approximate the volume-averaged temperature of battery cells in one of the modules of the battery pack with varying mass flow rate of cooling fluid using uniform heat source as inputs. The ROM runs orders of magnitude faster than the original CFD model. To reduce the time it takes to generate training data, used in building LPV ROM, a divide-and-conquer approach is introduced. This is done by dividing the battery module into a series of mid-cell and end-cell units. A mid-cell unit is composed of a cooling channel sandwiched in between two half -cells. A half-cell has half as much heat capacity as a full-cell. An end-cell unit is composed of a cooling channel sandwiched in between full-cell and a half-cell. A mass flow rate distribution look-up-table is generated from a set of steady-state simulations obtained by running the full CFD model at different inlet manifold mass flow rate samples.
2016-04-11
Journal Article
2016-01-9016
Mohammad Gerami Tehrani, Juuso Kelkka, Jussi Sopanen, Aki Mikkola, Kimmo Kerkkänen
Abstract The feasibility of improving the energy efficiency of Electric Vehicles (EV) by manipulating operation points by means of a variable transmission is investigated with an efficient mathematical model of power losses in all driveline components. Introduced model can be solved in real-time making it possible to embed it to a control scheme of EV. Empirical test results are employed to derive the efficiency of the power electronics and electric motor at operation points while the mechanical power losses are predicted by a comprehensive and generic formulation for efficiency analysis. The simulation model used comprises electrical component efficiency, drivetrain inertias, gearbox efficiency, regenerative braking, and gear ratio selection. Three different transmission types are studied in this work; a single reduction gear, a five-step gearbox and an Infinitely Variable Transmission.
2016-04-05
Technical Paper
2016-01-1075
Jonathan Plail, Petr Grinac, Helen Ballard
Abstract In this paper, a mathematical model for simulating the 3D dynamic response of a valve spring is described. The 3D model employs a ‘geometrically exact’ 3D beam connected between each mass of the discretised mass-elastic system. Shear deformations within the beam are also considered, which makes it a Timoshenko type finite element. Results from the 3D model are compared with results from a more conventional 1D model. To validate the results further, some results are compared with real test data that was gathered during a technical consulting project. In this project, a prototype valvetrain that was originally giving acceptable durability began to wear the spring seats when a new batch of springs were procured and tested. 1D and 3D simulation results were used to help understand the cause of the failure and to make recommendations to resolve the issue. Results showed that the 3D model was able to predict the spring seat loads with greater precision than the 1D spring could.
2016-04-05
Technical Paper
2016-01-1212
Yupu Chen, Miaohua Huang
Abstract Lithium-ion battery plays a key role in electric vehicles, which is critical to the system availability. One of the most important aspects in battery managements systems(BMS) in electric vehicles is the stage of health(SOH) estimation. The state of health (SOH) estimation is very critical to battery management system to ensure the safety and reliability of EV battery operation. The classical approach of current integration(coulomb counting) can't get the accurate values because of accumulative error. In order to provide timely maintenance and replacements of electric vehicles, several estimation approaches have been proposed to develop a reliable and accurate battery state of health estimation. A common drawback of previous algorithm is that the computation quantity is huge and not quite accurate, that is updated partially in this study.
2016-04-05
Journal Article
2016-01-1653
Zhenhai Gao, Jun Wang, Hongyu Hu, Dazhi Wang
Abstract Vehicle Longitudinal Control (VLC) algorithm is the basis function of automotive Cruise Control system. The main task of VLC is to achieve a longitudinal acceleration tracking controller, performance requirements of which include fast response and high tracking accuracy. At present, many control methods are used to implement vehicle longitudinal control. However, the existing methods are need to be improved because these methods need a high accurate vehicle dynamic model or a number of experiments to calibrate the parameters of controller, which are time consuming and costly. To overcome the difficulties of controller parameters calibration and accurate vehicle dynamic modeling, a vehicle longitudinal control algorithm based on iterative learning control (ILC) is proposed in this paper. The algorithm works based on the information of input and output of the system, so the method does not require a vehicle dynamics model.
2016-04-05
Technical Paper
2016-01-1622
Miroslav Mokry
Abstract Lagally’s theorem is used to evaluate the increments to aerodynamic forces on automotive models, tested in solid-wall wind tunnels. The strengths of the model-representing singularities, pre-requisite for the application of the theory, are obtained from experimental wall pressure data, using an influence matrix method. The technique is demonstrated on the drag force acting on full-size and half-size truck models, measured in the same test section.
2016-04-05
Technical Paper
2016-01-1557
Francesco Castellani, Nicola Bartolini, Lorenzo Scappaticci, Davide Astolfi, Matteo Becchetti
Abstract Shock absorber is one of the most relevant sub-systems of the suspension system for a wide range of vehicles. Although a high level of development and tuning has been reached, in order to ensure high safety standards in almost every situation, some dynamic phenomena affecting vehicle handling or NHV (Noise Vibration Harshness) can appear. The aim of present work is to improve a mathematical model using experimental data from a prototype of monotube shock absorber developed for research purposes. The model takes into account all the main features affecting the global performance of the device, such as non-linear behaviour and the presence of hysteresis loops. Actually, the most important parameters are analyzed, such as flow and orifice coefficients of the valves, coefficients of mechanical compliance of the chambers and oil compressibility, dry and viscous friction coefficients.
2016-04-05
Technical Paper
2016-01-0960
Arifumi Matsumoto, Kenji Furui, Makoto Ogiso, Toru Kidokoro
Abstract Urea selective catalytic reduction (SCR) systems are a promising technology for helping to lower NOx emissions from diesel engines. These systems also require on-board diagnostic (OBD) systems to detect malfunctioning catalysts. Conventional OBD methodology for a SCR catalyst involves the measurement of NOx concentration downstream of the catalyst. However, considering future OBD regulations, erroneous diagnostics may occur due to variations in the actual environment. Therefore, to enhance OBD accuracy, a new methodology was examined that utilizes NH3 slip as a new diagnostic parameter in addition to NOx. NH3 slip increases as the NOx reduction performance degrades, because both phenomena are based on deterioration in the capability of the SCR catalyst to adsorb NH3. Furthermore, NH3 can be measured by existing NOx sensors because NH3 is oxidized to NO internally. To make use of NH3 slip, an estimation model was developed.
2016-04-05
Journal Article
2016-01-1655
Benjamin Hirche, Beshah Ayalew
This paper presents the application of a proposed fuzzy inference system as part of a stability control design scheme implemented with active steering actuator sets. The fuzzy inference system is used to detect the level of overseer/understeer at the high level and a speed-adaptive activation module determines whether an active front steering, active rear steering, or active 4 wheel steering is suited to improve vehicle handling stability. The resulting model-free system is capable of minimizing the amount of model calibration during the vehicle stability control development process as well as improving vehicle performance and stability over a wide range of vehicle and road conditions. A simulation study will be presented that evaluates the proposed scheme and compares the effectiveness of active front steer (AFS) and active rear steer (ARS) in enhancing the vehicle performance. Both time and frequency domain results are presented.
2016-04-05
Journal Article
2016-01-0094
Jaya Gaitonde, R B Lohani
Abstract Photodetectors are important components in automotive industry. Sensitivity, speed, responsivity, quantum efficiency, photocurrent gain and power dissipation are the important characteristics of a photodetector. We report a high performance photodetector based on GaAs Metal- Semiconductor Field Effect Transistor (MESFET), with very high responsivity, excellent quantum efficiency, high sensitivity, moderate speed, tremendous gain and low power dissipation, surpassing their photodiode, phototransistor and other counterparts. A theoretical model of GaAs front illuminated Optical Field Effect transistor is presented. The photovoltaic and photoconductive effects have been taken into account. The gate of the OPFET device has been left open to make a reduction in the number of power supplies. The results are in line with the experiments. The device shows high potential in automotive applications.
2016-04-05
Journal Article
2016-01-0103
Ludwig Brabetz, Mohamed Ayeb, Oliver Baumgarten
Abstract The topology of an EDS, defined by the routing paths and by the location of the distribution boxes and the inline connectors, has a strong impact on weight and required amount of material, especially of copper, as well as on the manufacturing- and assembly time. Although a good part of the routing and packaging is fixed due to technical reasons and carry-over situations, in general there are enough optional paths and locations to allow up to several thousand alternative topologies. For these reasons, an optimization is possible as well as important. For such an optimization, in this paper a method is presented to concurrently minimize predefined criteria, e.g. the required copper, length of the wires, and the overall length of the wire bundles. It is based on designated algorithms for the variation of the topology, the routing, and the calculation of the optimization criteria as mentioned above.
2016-04-05
Journal Article
2016-01-0142
Zheng Wang, Weiwen Deng, Sumin Zhang, Jianpeng Shi
Abstract In this paper, we present a model predictive controller for the autonomous vehicle lane-change maneuver. Firstly, an optimal trajectory is generated by polynomial, then, utilize it as the reference trajectory of the controller. It is well known that vehicle with nonholonomic constraints can not be feedback stabilized through continuously differentiable, time-invariant control laws. One of the advantages of MPC is the ability to handle constraints in a straightforward way. Quadratic programming is used to solve a linear MPC by successive linearization of an error model of the vehicle. Due to that the vehicle dynamics model is used, in order to prevent optimal solution cannot be obtained within the prescribed time, the relaxation factor in the objective function.
2016-04-05
Technical Paper
2016-01-0227
Kaushal Kumar Jha, Imran Shaik
Abstract Heat exchangers are thermoregulatory system of an automotive air conditioning system. They are responsible for heat exchange between refrigerant and air. Sizing of the heat exchanger becomes critical to achieve the required thermal performance. In the present work, the behavior of heat exchanger with respect to change in size is studied in detail by developing a scaling model. The limited experiments have been conducted for 3 different condensers. Commercially available 1D tool GT Suite is used for simulations. The heat exchangers are modeled using COOL3D module of GT Suite. The experimental thermal capacities of heat exchanger are compared with the simulated values. A good agreement up to ±2.3% is found between the experiments and simulations. Then developed scaling model in GT Suite is used for predicting the thermal behavior of heat exchangers by changing the size of the heat exchanger.
2016-04-05
Technical Paper
2016-01-0229
Mohammed Ismail, Shahram Fotowat, Amir Fartaj
Abstract A numerical study is performed to investigate the transient heat transfer and flow characteristics of aluminum oxide (Al2O3) nanoparticles dispersed in 50:50 ethylene glycol/water (EG/W) base fluid in a multipass crossflow minichannel heat exchanger. The time dependent thermal responses of the system in a laminar regime are predicted by solving the conservation equations using the finite volume method and SIMPLE algorithm. The transient regime is caused by a step change of nanofluid mass flow rate at the inlet of the minichannel heat exchanger. This step change can be analogous with a thermostat operation. In this study, three volume fractions up to 3 percent of Al2O3 nanoparticles dispersed to the base fluid EG/W are modeled and analyzed. In the numerical simulation, Al2O3-EG/W nanofluid is considered as a homogenous single-phase fluid. An analysis of the transient response for the variation of nanofluids volume concentrations is conducted.
2016-04-05
Technical Paper
2016-01-0219
Song Lan, Zhijia Yang, Richard Stobart, Edward Winward
Abstract An automotive engine can be more efficient if thermoelectric generators (TEG) are used to convert a portion of the exhaust gas enthalpy into electricity. Due to the relatively low cost of the incoming thermal energy, the efficiency of the TEG is not an overriding consideration. Instead, the maximum power output (MPO) is the first priority. The MPO of the TEG is closely related to not only the thermoelectric materials properties, but also the operating conditions. This study shows the development of a numerical TEG model integrated with a plate-fin heat exchanger, which is designed for automotive waste heat recovery (WHR) in the exhaust gas recirculation (EGR) path in a diesel engine. This model takes into account the following factors: the exhaust gas properties’ variation along the flow direction, temperature influence on the thermoelectric materials, thermal contact effect, and heat transfer leakage effect. Its accuracy has been checked using engine test data.
2016-04-05
Technical Paper
2016-01-0285
Salah H. R. Ali, Mohammed A. H. Khalafalla, Ihab H. Naeim, Sarwat Z. A. Zahwi
Abstract Straightness uncertainty in dimensional metrology is an important parameter in precision engineering. Optimization in straightness measurement using soft algorithm techniques is widely encountered solution in coordinate metrology. In this work, we report on the uncertainty in the CMM measurement of straightness feature for a slab surface. Straightness points have been measured precisely in 3D using CMM at NIS. The straightness has been analyzed using a Particle Swarm Optimization (PSO) algorithm. The probability density distribution of the measured spatial straightness was developed using a Sequential Monte Carlo (SMC) technique; forming probability density histogram with 95% confidence level representing an uncertainty in the straightness measurement. Comparison with relevant reports showed and approved that our results are more accurate since we used a computationally efficient modified SMC technique and PSO algorithm.
2016-04-05
Technical Paper
2016-01-0334
Lucas e Silva, Tennakoon Mudiyanselage Tennakoon, Mairon Marques, Ana M. Djuric
Abstract A collaborative robot or cobot is a robot that can safely and effectively interact with human workers while performing industrial tasks. The ability to work alongside humans has increased the importance of collaborative robots in the automation industry, as this unique feature is a much needed property among robots nowadays. Rethink Robotics has pioneered this unique discipline by building many robots including the Baxter Robot which is exclusive not only because it has collaborative properties, but because it has two arms working together, each with 7 Degrees Of Freedom. The main goal of this research is to validate the kinematic equations for the Baxter collaborative robot and develop a unified reconfigurable kinematic model for the Left and Right arms so that the calculations can be simplified.
2016-04-05
Technical Paper
2016-01-0624
Benedikt Raidt
Abstract A local Gaussian process regression approach is presented, which allows to model nonlinearities of internal combustion engines more accurate than global Gaussian process regression. By building smaller models, the prediction of local system behavior improves significantly. In order to predict a value, the algorithm chooses the nearest training points. The number of chosen training points depends on the intensity of estimated nonlinearity. After determining the training points, a model is built, the prediction performed and the model discarded. The approach is demonstrated with a benchmark system and air charge test bed measurements. The measurements are taken from a turbocharged SI gasoline engine with both variable inlet valve lift and variable inlet and exhaust valve opening angle. The results show how local Gaussian process regression outmatches global Gaussian process regression concerning model quality and nonlinearities in particular.
2016-04-05
Technical Paper
2016-01-0699
Jacob McKenzie, Wai K. Cheng
Abstract An ignition delay correlation encompassing the effects of temperature, pressure, residual gas, EGR, and lambda (on both the rich and lean sides) has been developed. The procedure uses the individual knocking cycle data from a boosted direct injection SI engine (GM LNF) operating at 1250 to 2000 rpm, 8-14 bar GIMEP, EGR of 0 to 12.5%, and lambda of 0.8 to 1.3 with a certification fuel (Haltermann 437, with RON=96.6 and MON=88.5). An algorithm has been devised to identify the knock point on individual pressure traces so that the large data set (of some thirty three thousand cycles) could be processed automatically. For lean and for rich operations, the role of the excess fuel, air, and recycled gas (which has excess air in the lean case, and hydrogen and carbon monoxide in the rich case) may be treated effectively as diluents in the ignition delay expression.
2016-04-05
Technical Paper
2016-01-0174
Jun Ni, Jibin Hu, Xueyuan Li, Bin Xu, Junjie Zhou
Abstract In order to discuss the limit handling performance of a FSAE race car, a method to generate the G-G diagram was proposed based on phase plane concept. The simulated G-G diagram was validated by experiments with an electric FSAE race car. In section 1, a nonlinear 7 DOFs dynamic model of a certain electric FSAE race car was built. The tire mechanical properties were described by Magic Formula, and the tire test data was provided by FSAE TTC. In section 2, firstly the steady-state yaw rate response was discussed in different vehicle speed and lateral acceleration based on the simulations. Then the method to generate the G-G diagram based on phase plane concept was proposed, and the simulated G-G diagram of a certain FSAE race car was obtained. In section 3, the testbed FSAE race car was described, including the important apparatuses used in the experiments. Based on the race track experiment, the G-G diagram of the race car was obtained.
2016-04-05
Technical Paper
2016-01-0172
Tim Tudor, Kerry Tudor
This paper presents an investigation into the effect of front wheel steer geometry on steer induced load transfer. An inhouse mathematical model has been developed which quantifies and illustrates these effects. The model has also been used to predict how common geometry variables affect the resulting steer induced load transfer. It is shown that the effect of steer on overall load transfer is significant, especially for high roll stiffness vehicles, and that the effect may be used to manipulate vehicle handling balance. The paper also shows that the resulting load transfer can be controlled by utilising an upright mounted pushrod design and how such a configuration may also be used to control front ride height with steer. The relationships between common design variables and the resulting steer effect have been determined.
2016-04-05
Journal Article
2016-01-0568
Matthew C. Robinson, Nigel N. Clark, Parviz Famouri
Abstract Recent free piston engine research reported in the literature has included development efforts for single and dual cylinder devices through both simulation and prototype operation. A single cylinder, spring opposed, oscillating linear engine and alternator (OLEA) is a suitable architecture for application as a steady state generator. Such a device could be tuned and optimized for peak efficiency and nominal power at unthrottled operation. One of the significant challenges facing researchers is startup of the engine. It could be achieved by operating the alternator in a motoring mode according to the natural system resonant frequency, effectively bouncing the translator between the spring and cylinder, increasing stroke until sufficient compression is reached to allow introduction of fuel and initiation of combustion. To study the natural resonance of the OLEA, a numeric model has been built to simulate multiple cycles of operation.
2016-04-05
Technical Paper
2016-01-1384
Mengshi Deng, Jian Lan
Abstract Glass lifter is a key part of automobile door system. Guide rail is the carrier of glass lifter, and it bears various load cases when glass lifer works. Mass, stiffness and natural frequencies are the factors that influence the performance of glass lifter. In order to design a lighter and reasonable glass lifter, topology optimization methods are studied in this paper. In a rope-wheel glass lifter, design domain is determined by the mechanical structure and working conditions. Firstly, the single target continuum structure topology optimization mathematic models of guide rail are built in this paper, and analysis of multi-stiffness topology optimization are carried out accordingly in which volume fraction is set as 0.4, 0.5 and 0.6. These models are based on SIMP (Solid Isotropic Material with Penalization) theory.
2016-04-05
Journal Article
2016-01-1303
Haiqing Xu, Chang Jin, Hong Zhou, Yi Zhou
Abstract On the study of reducing the disturbance on driver’s attention induced by low frequency vehicle interior stationary noise, a subjective evaluation is firstly carried out by means of rank rating method which introduces Distraction Level (DL) as evaluation index. A visual-finger response test is developed to help evaluating members better recognize the Distraction Level during the evaluation. A non-linear back propagation artificial neural network (BPANN) is then modeled for the prediction of subjective Distraction Level, in which linear sound pressure RMS amplitudes of five Critical Band Rates (CBRs) from 20 to 500Hz are selected as inputs of the model. These inputs comprise an input vector of BPANN. Furthermore, active noise equalization (ANE) on DL is realized based on Filtered-x Least Mean Square (FxLMS) algorithm that controls the gain coefficients of inputs of trained BPANN.
2016-04-05
Technical Paper
2016-01-1309
Yingping Lv, Yongchang Du, Yujian Wang
Abstract In this paper, analysis methods for brake squeal including substructure modal composition analysis and substructure modal parameters sensitivity analysis are presented. These methods are based on a new closed-loop coupling disc brake model, where the coupled nodal pairs in each coupling interface are connected tightly. This assumption is different from other existing models in literatures, where the interface nodes are coupled through assumed springs. Based on this new model, two analysis methods are derived: Substructure modal composition analysis indicates the contribution of modes of each substructure to the noise mode; Substructure modal parameters sensitivity analysis indicates the sensitivity of the real part of system’s eigenvalue to component’s modal frequency and shape. Finally, the presented analysis methods are applied to analyse a high frequency squeal problem of a squealing disc brake.
2016-04-05
Technical Paper
2016-01-0011
Salah Alhasia, Sharif Gindy, Badih Jawad, Chris Riedel, Selin Arslan
Abstract Bearings are a major component in any rotating system. With continually increasing speeds, bearing failure modes take new unconventional forms that often are not understood. In high speed applications, rolling element forces and gyroscopic moments can be significantly high compared to the applied forces acting on a bearing. Such moments create a “driving” torque causing outer race to creep. In this paper a mathematical model for the dynamics of a rolling element in a high speed bearing is derived. Preload values counterbalancing the torque driving the outer race to rotate can be predicted from this model. An attempt to experimentally measure this torque using a specially designed apparatus with integrated strain gauge torque sensor is also described. Both model and experimental measurements are aimed at understanding, and therefore preventing bearing failures due to outer race (creep) rotations.
2016-04-05
Technical Paper
2016-01-0031
Wenxu Niu, Ke Song, Yucheng He, Tong Zhang
Abstract X-in-the-loop (XiL) framework is a new validation concept for vehicle product development, which integrates different virtual and physical components to improve the development efficiency. With XiL platform the requirements of reproducible test, optimization and validation, in which hardware, equipment and test objects are located in different places, could be realized. In the view of different location and communication form of hardware, equipment and test objects, time delay problem exists in the XiL platform, which could have a negative impact on development and validation process. In this paper, a simulation system of time delay prediction and compensation is founded with the help of BP neural network and RBF neural network. With this simulation system the effect of time delay in a vehicle dynamic model as well as tests of geographically distributed vehicle powertrain system is improved during the validation process.
2016-04-05
Technical Paper
2016-01-0100
Sushant Kishor Hingane
High-end vehicles with latest technology and autonomous driving experience have to bear the cost of increasing number of sensors on-board. It would be beneficial to reduce some of the sensors in the vehicle and make use of other available resources, retaining the same functionality. This paper discusses a novel technique of estimating the weight of seat occupant from an already existing DC motor without using additional pressure sensors. Passenger weight information is important for seat-belt reminder system as well as supplemental restraint system that will decide the air-bag deployment. The mathematical model for a series-type DC motor is analyzed and simulated using MATLAB. Further, results of the experiment performed on a lower capacity motor are shared and compared with the simulation results. Formulating a linear relation gives a possibility to develop a device for occupant weight measurement inside the high-end vehicles.
2016-04-05
Journal Article
2016-01-0584
Vesselin Krassimirov Krastev, Gino Bella
Abstract Turbulence modeling is a key aspect for the accurate simulation of ICE related fluid flow phenomena. RANS-based turbulence closures are still the preferred modeling framework among industrial users, mainly because they are robust, not much demanding in terms of computational resources and capable to extract ensemble-averaged information on a complete engine cycle without the need for multiple cycles simulation. On the other hand, LES-like approaches are gaining popularity in recent years due to their inherent scale-resolving nature, which allows the detailed modeling of unsteady flow features such as cycle-to-cycle variations in a DI engine. An LES requires however a large number of simulated engine cycles to extract reliable flow statistics, which coupled to the higher spatial and temporal resolution compared to RANS still poses some limits to a wider application of such methodology on realistic engine geometries.
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