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Viewing 1 to 30 of 18401
2015-09-06
Technical Paper
2015-24-2385
Guillaume Alix, Jean-Charles Dabadie, Gregory Font
Legal constraints concerning CO2 emissions have made the improvement of light duty vehicle efficiency mandatory. In result, vehicle powertrain and its development have become increasingly complex, requiring the ability to assess rapidly the effect of several technological solutions, such as hybridization or internal combustion engine (or ICE) downsizing, on vehicle CO2 emissions. In this respect, simulation is nowadays a common way to estimate a vehicle’s fuel consumption on a given driving cycle. This estimation can be done with the knowledge of vehicle main characteristics, its transmission ratio and efficiency and its internal combustion engine (ICE) fuel consumption map. While vehicle and transmission parameters are relatively easy to know, the ICE consumption map has to be obtained through either test bench measurements or computation.
2015-09-06
Technical Paper
2015-24-2410
Stefania Falfari, Claudio Forte, Gian Bianchi, Giulio Cazzoli, Cristian Catellani, Lucio Postrioti, Fabrizio Ottobre
In the next incoming future the necessity of reducing the raw emissions leads to the challenge of an increment of the thermal engine efficiency. In particular it is necessary to increase the engine efficiency not only at full load but also at partial load conditions. In the open literature very few technical papers are available on the partial load conditions analysis. In the present paper the analysis of the effect of the throttle valve rotational direction on the mixture formation is analyzed. The engine was a PFI 4-valves motorcycle engine. The engine geometry was formed by the intake duct and the cylinder. The throttle valve opening angle was 17.2 deg, which lays between the very partial load and the partial load condition. The CFD code adopted for the analysis was the FIRE AVL code v. 2013.2. The intake and the compression phases till TDC were simulated: inlet boundary conditions from 1D simulations were imposed.
2015-09-06
Technical Paper
2015-24-2512
Barouch Giechaskiel, Alessandro Zardini, Giorgio Martini
In 2009 a particle number (PN) limit was introduced in the European Union vehicle exhaust legislation for diesel passenger cars. The PN method requires measurement of solid particles (i.e. those that do not evaporate at 350°C) above 23 nm. In 2013 the same approach was introduced in the heavy duty engines legislation. The same approach will be added for gasoline direct injection vehicles from 2017. This decision was based on a long evaluation that concluded that there is no significant sub23nm fraction for this technology. In this paper we examine the suitability of the current PN method for mopeds and motorcycles. Emission levels of >10 mopeds and motorcycles are presented. Special attention is given to sub23nm emission levels for some of them. The investigation was conducted with PN legislation compliant systems with counters measuring above 23nm and 10nm.
2015-09-06
Technical Paper
2015-24-2529
Riccardo Russo, Salvatore Strano, Mario Terzo
The yaw moment control systems are adopted in order to enhance the handling and to prevent the vehicle unstable behaviour. They can be substantially divided in three sub-categories: systems based on differential braking, systems based on the controlled torque distribution, and steer by wire systems. With reference to the torque distribution systems, they are substantially characterized by limited slip differentials able to generate an internal locking torque that allows to differentiate the output torque and to generate a corrective yaw moment on the vehicle. This paper deals with a new automotive controllable differential for the control of the yaw moment of the vehicle. Software simulations are presented in order to evaluate the benefits reachable by means of the proposed device. The device is based on the employment of magnetorheological fluid, whose magnetization allows to generate the locking torque and, consequently, the improving yaw moment.
2015-09-06
Technical Paper
2015-24-2538
Lars Christian Riis Johansen, Ingemar Denbratt, Stina Hemdal
The emissions from a parallel hybrid combustion engine and electric powertrain on the NEDC and FTP75 drive cycles has been investigated in order to determine the relation between emissions and the road and engine load profile. The time resolved particulate number and size distribution was measured in addition to unburned hydrocarbons (UHC) and NOx. Cold and hot powertrain starts were conducted for both drive cycles. The combustion engine was a three cylinder spark ignited direct injection (SIDI) turbocharged engine fuelled with gasoline. Particulate emission peaked during acceleration from idling during both cold and hot drive cycle starts. Particulates during startup and acceleration from idling were characterized by particles smaller than 100nm. During periods of constant large engine load the particle numbers in the region of 100nm increased. UHC similarly peaked during acceleration from engine idling. NOx depended predominantly on engine load.
2015-09-06
Technical Paper
2015-24-2539
Joao P. Ribau, Susana M. Vieira, Joao M. C. Sousa, Carla M. Silva
This study aims to find the best alternative vehicle to replace a conventional diesel bus operating in urban environments, aiming to reduce the carbon footprint and be financially advantageous. A multi-objective metaheuristic method is used to optimize battery electric, internal combustion engine powered hybrid, and fuel cell powered hybrid powertrains, including plug-in versions, concerning the powertrain components design and the energy management strategy parameters, which are the optimization variables. The optimization objective is to minimize the life cycle (LC) environmental impact and maximize the positive financial balance of each proposed powertrain without compromising the driving performance. The various powertrain solutions compose a trade-off set of nondominated solutions (Pareto-front approximation), where different importance is given to each objective function.
2015-09-06
Technical Paper
2015-24-2542
Carmelina Abagnale, Salvatore Strano, Massimo Cardone, Paolo Iodice, Mario Terzo, Giovanni Vorraro
The paper describes the development of an innovative test rig for the evaluation of e-bikes in terms of energetic performances, pollutant emissions and control system. The test rig has been realized starting from a commercial cyclist training system and operating on it substantial modifications. The test rig is able to reproduce an aforethought route or paths acquired during road tests. Through the installed sensors and data acquisition system, it is possible to measure the performance of the e-bike in terms of instantaneous power and speed. The experimental test rig can simulate the resistant torque of a predetermined track and allows to test and optimize the control strategy available on the electronic control unit (ECU). A fundamental feature of the system is constituted by the possibility of adopting a hardware in the loop approach for the testing of the e-bike and of its control.
2015-09-06
Technical Paper
2015-24-2544
Fernando Ortenzi, Giovanni Pede, Pierluigi Antonini
Within the “Industria 2015” Italian framework program, the HI-ZEV project has the aim to develop two high performance vehicles: one full electric and one hybrid. The hybrid vehicle is a sport car with an internal combustion engine with a maximum power of 300 kW and an electric motor with a maximum power of 150 kW. It is equipped with a 400 V, 15 Ah storage system. Special batteries are required due to the high values of discharge current needed to supply the electric subsystem (up to 25 times the nominal current). Also a dedicated cooling system has been designed, to avoid a dangerous rising temperature, due to such high currents. The cells used have been the Demon 5Ah OCCL (Oxygen-Cobalt-Carbon-Li-Ion technology). Every single module is composed by 6 cells in series with 22.5V of nominal voltage, while the battery pack is made with 18 modules in series and 3 in parallel.
2015-09-06
Technical Paper
2015-24-2546
Davide Di Battista, Carlo Villante, Roberto Cipollone
Alternative vehicle powertrains (hybrid, hydrogen, electric) are the only possible solution for environmental problems afflicting urban areas. Electric and hybrid vehicles are now slowly taking place in the automotive sector, while mostly thanks to the international regulations that incentive manufactures to have a share of such vehicles in their fleet. On a Well To Wheels (WTW) basis, the most effective alternative powertrain is surely represented by fuel cell vehicles, which convert fuel energy directly in electric energy with a higher overall conversion efficiency than a thermal engine. The design and optimization of this kind of vehicles and powertrains, however, is not straightforward, and can be guided by proper mathematical modeling approaches, considering energetic as well as physical characteristics of all the components.
2015-09-06
Technical Paper
2015-24-2543
Damien Maroteaux, Damien Le Guen, Eric Chauvelier
The worldwide trends for future CO2 regulation standards will push car manufacturers for more and more development of Electric and Hybrid Electric Vehicles. Many different configurations of Hybrid Electric Vehicles exist, including parallel hybrid, series hybrid, plug-in hybrids, Battery Electric Vehicles with Range Extender, etc. The choice of the optimal architecture depends on many different parameters, and is a key issue to be solved at the beginning of vehicle development. In order to help decision making in the early phase of projects, simulation tools are essential. A specific simulation platform for simulation of fuel economy and CO2 emissions for hybrid electric vehicles has been developed by Renault.
2015-09-06
Technical Paper
2015-24-2545
Florian Winke, Hans-Juergen Berner, Michael Bargende
Due to the increased complexity of hybrid vehicle technology, development of powertrains for hybrid electric vehicles (HEV) can only be performed efficiently by using modern simu-lation technologies. The dimensioning of drivetrain components has to be addressed in a very early phase of the development process, which is why predictive models are of particular importance. This study presents a comparison of different approaches for the simulation of HEV fuel consumption. For this purpose, “traditional” mapped combustion engine models are com-pared to different types of 1D-CFD engine models (GT-Power), paired with a quasi dimen-sional, predictive combustion model (FKFS User Cylinder). To ensure an efficient devel-opment process, simplified engine models are used, which are able to reduce computing time significantly while generally remaining the complete potential of the model.
2015-07-01
Journal Article
2015-01-9143
Gabriel Pouliot, Marc-Olivier Lacerte, Jean-Sebastien Plante, Philippe Micheau
This paper presents the design and experimental validation of an eddy current torque transfer clutch for use inside Automated Manual Transmissions (AMTs) to perform seamless gear upshifts. Electric vehicles (EVs) with a single-ratio gearbox may provide high levels of smoothness, but using a multi-speed gearbox provides significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. AMTs can provide smooth shifts without torque interruption when coupled to a normally-open torque bypass clutch. However, conventional dry friction clutches are not best suited for such torque bypass due to wear and controllability concerns, while wet clutches would decrease powertrain efficiency due to viscous losses. An eddy current clutch would be highly controllable, simple to manufacture, low-cost, robust, and do not wear compared to friction clutches.
2015-07-01
Journal Article
2015-01-9108
Arash Mehdizadeh Gavgani, Timothy Bingham, Aldo Sorniotti, John Doherty, Carlo Cavallino, Marco Fracchia
Abstract This paper discusses the torque-fill capability of a novel hybrid electric drivetrain for a high-performance passenger car, originally equipped with a dual-clutch transmission system, driven by an internal combustion engine. The paper presents the simulation models of the two drivetrains, including examples of experimental validation during upshifts. An important functionality of the electric motor drive within the novel drivetrain is to provide torque-fill during gearshifts when the vehicle is engine-driven. A gearshift performance indicator is introduced in the paper, and the two drivetrain layouts are assessed in terms of gearshift quality performance for a range of maneuvers.
2015-07-01
Journal Article
2015-01-9111
Lasse G. Andersen, Jesper K. Larsen
Abstract Coast-down modeling has been widely used to assess vehicle aerodynamic drag and rolling resistance by fitting a vehicle resistance model to speed measurements and thereby get an estimate on model parameters. Here a coast-down model is used for assessing how road surface characteristics influence rolling resistance. Parameter estimation as well as an extensive perturbation analysis of the parameter fit with respect to data noise has been performed. Functional Data Analysis (FDA) is introduced and discussed as a tool for this. It is concluded that FDA is a powerful tool for 1) approximating derivatives, 2) assessing the degree of smoothing of the data 3) handling noise sources in the perturbation analysis and 4) enabled numerical solutions of the coast-down Ordinary Differential Equation (ODE) model. Investigations showed that MPD was the most important parameter compared to IRI although MPD data required smoothing for optimal model fit.
2015-07-01
Journal Article
2015-01-9112
Shahyar Taheri, Terence Wei
Modeling the tire forces and moments (F&M) generation, during combined slip maneuvers, which involves cornering and braking/driving at the same time, is essential for the predictive vehicle performance analysis. In this study, a new semi-empirical method is introduced to estimate the tire combined slip F&M characteristics based on flat belt testing machine measurement data. This model is intended to be used in the virtual tire design optimization process. Therefore, it should include high accuracy, ease of parameterization, and fast computational time. Regression is used to convert measured F&M into pure slip multi-dimensional interpolant functions modified by weighting functions. Accurate combined slip F&M predictions are created by modifying pure slip F&M with empirically determined shape functions. Transient effects are reproduced using standard relaxation length equations. The model calculates F&M at the center of the contact patch.
2015-06-15
Journal Article
2015-01-2331
Alexander Schell, Vincent Cotoni
Abstract Aero-vibro-acoustic prediction of interior noise associated with exterior flow requires accurate predictions of both fluctuating surface pressures across the exterior of a vehicle and efficient models of the vibro-acoustic transmission of these surface pressures to the interior of a vehicle. The simulation strategy used in this paper combines both CFD and vibro-acoustic methods. An accurate excitation field (which accounts for both hydrodynamic and acoustic pressure fluctuations) is calculated with a hybrid CAA approach based on an incompressible unsteady flow field with an additional acoustic wave equation. To obtain the interior noise level at the driver's ears a vibro-acoustic model is used to calculate the response of the structure and interior cavities. The aero-vibro-acoustic simulation strategy is demonstrated for a Mercedes-Benz S-class and the predictions are compared to experimental wind tunnel measurements.
2015-06-15
Technical Paper
2015-01-2329
Paolo Di Francescantonio, Charles Hirsch, Piergiorgio Ferrante, Katsutomo Isono
Abstract A new method called Adaptive Spectral Reconstruction (ASR) for the stochastic reconstruction of broadband aeroacoustic sources starting from steady CFD analyses is presented and applied to the evaluation of the noise radiated by a model automotive side mirror. The new approach exploits some ideas from both SNGR and RPM, and for some aspects can be considered as a sort of mixing between the two methods since it permits to reconstruct both the frequency content of the turbulent field (as done by SNGR) and the spatial cross correlation (as done by RPM). The turbulent field is reconstructed with a sum of convected plane waves, but two substantial differences are introduced in respect of SNGR. The first difference concerns the spatial variation of the parameters that define each wave, that depends on the wavelength of each wave, rather than being kept constant or related to the CFD correlation length.
2015-06-15
Journal Article
2015-01-2330
Christian Y. Glandier, Mark Eiselt, Oskar Prill, Eric Bauer
Abstract With the reduction of engine and road noise, wind has become an important source of interior noise when cruising at highway speed. The challenges of weight reduction, performance improvement and reduced development time call for stronger support of the development process by numerical methods. Computational Fluid Dynamics (CFD) and finite element (FE) vibroacoustic computations have reached a level of maturity that makes it possible and meaningful to combine these methods for wind noise prediction. This paper presents a method used for coupling time domain CFD computations with a finite element vibroacoustic model of a vehicle for the prediction of low-frequency wind noise below 500 Hz. The procedure is based on time segmentation of the excitation load and transformation into the frequency domain for the vibroacoustic computations. It requires simple signal processing and preserves the random character as well as the spatial correlation of the excitation signal.
2015-06-15
Technical Paper
2015-01-2326
Denis Blanchet, Anton Golota
Abstract Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities. The main physical mechanisms related to noise generation within a turbulent flow and the vibro-acoustic transmission through the vehicle greenhouse is nowadays better understood. Several simulation methods such as CFD, FEM, BEM, FE/SEA Coupled and SEA can be coupled together to represent the physical phenomena involved. The main objective being to properly represent the convective and acoustic component within the turbulent flow to ensure proper computation of the wind noise contribution to the interior SPL of a vehicle.
2015-06-15
Journal Article
2015-01-2307
Neil Figurella, Rick Dehner, Ahmet Selamet, Keith Miazgowicz, Ahsanul Karim, Ray Host
Abstract The effect of aerodynamically induced pre-swirl on the acoustic and performance characteristics of an automotive centrifugal compressor is studied experimentally on a steady-flow turbocharger facility. Accompanying flow separation, broadband noise is generated as the flow rate of the compressor is reduced and the incidence angle of the flow relative to the leading edge of the inducer blades increases. By incorporating an air jet upstream of the inducer, a tangential (swirl) component of velocity is added to the incoming flow, which improves the incidence angle particularly at low to mid-flow rates. Experimental data for a configuration with a swirl jet is then compared to a baseline with no swirl. The induced jet is shown to improve the surge line over the baseline configuration at all rotational speeds examined, while restricting the maximum flow rate. At high flow rates, the swirl jet increases the compressor inlet noise levels over a wide frequency range.
2015-06-15
Technical Paper
2015-01-2301
Maxwell Hill, Dan Luo, Mark Moeller
Abstract Wind noise can be a significant event for automotive design engineers. The greenhouse glass plays an important role in the wind noise process. Robust estimates of the greenhouse glass damping are necessary for both understanding and modeling the role of the glass in the wind noise process. One unanswered question is whether the aerodynamic loads affect the window glass damping. To make this determination a method to assess the operational damping is required. The civil engineering community uses the random decrement technique to assess operational damping due to wind loads. The random decrement technique has been shown to be a normalized autocorrelation function. In this paper the damping is estimated directly from the autocorrelation function. In the first section the relationship between the damping and autocorrelation function is examined for white noise excitation. A single oscillator is examined as the first case. Extension to higher modal densities is discussed.
2015-06-15
Technical Paper
2015-01-2302
Yuksel Gur, Jian Pan, David Wagner
Lightweighting of vehicle panels enclosing vehicle cabin causes NVH degradation since engine, road, and wind noise acoustic sources propagate to the vehicle interior through these panels. In order to reduce this NVH degradation, there is a need to develop new NVH sound package materials and designs for use in lightweight vehicle design. Statistical Energy Analysis (SEA) model can be an effective CAE design tool to develop NVH sound packages for use in lightweight vehicle design. Using SEA can help engineers recover the NVH deficiency created due to sheet metal lightweighting actions. Full vehicle SEA model was developed to evaluate the high frequency NVH performance of “Vehicle A” in the frequency range from 200 Hz to 10 kHz. This correlated SEA model was used for the vehicle sound package optimization studies. Full vehicle level NVH laboratory tests for engine and tire patch noise reduction were also conducted to demonstrate the performance of sound package designs on “Vehicle A”.
2015-06-15
Technical Paper
2015-01-2353
Jan Bunthoff, Frank Gauterin, Christoph Boehm
Abstract In an automotive suspension, the shock absorber plays a significant role to enable the vehicle performances, especially in ride, handling and Noise-Vibration-Harshness (NVH). Understanding its physical characteristics is of great importance, as it has a main influence on the overall vehicle performance. Within this research project simulation models for different passive monotube shock absorber systems have been created in a 1-D system simulation software. The simulation models are designed and parameterized physically. To validate the simulation models measurements on different hydropulse-shaker with specially designed control signals to investigate the response during high frequency excitation, have been done. A detailed discussion of the several models and results of a simulation to measurement comparison is given. After detailed investigation the shock absorber simulation models are now adaptable to the multi body simulation.
2015-06-15
Journal Article
2015-01-2364
Xianpai Zeng, Jared Liette, Scott Noll, Rajendra Singh
Abstract The vibration isolation effectiveness of powertrain mount configurations is examined for electric vehicle application by considering the effect introduced by internal mount resonances. Unlike internal combustion engines where mounts are typically designed only for static support and low frequency dynamics, electric motors have higher excitation frequencies in a range where mount resonances often occur. The problem is first analytically formulated by considering a simple 3-dimensional powertrain system, and the vibration isolation effectiveness significantly deteriorates at the mount resonance(s). It is shown that by modifying the mount shape, the mount resonance(s) can be shifted while maintaining the same static rate, tuning the frequency away from any engine excitation or natural frequencies. Further, internal mount resonances are utilized to improve vibration isolation over a narrow frequency range, using non-identical mounts to split mount resonance peaks.
2015-06-15
Technical Paper
2015-01-2367
David Lennström, Arne Nykänen
Abstract When it comes to the acoustic properties of electric cars, the powertrain noise differs dramatically compared to traditional vehicles with internal combustion engines. The low frequency firing orders, mechanical and combustion noise are exchanged with a more high frequency whining signature due to electromagnetic forces and gear meshing, lower in level but subject to annoyance. Previous studies have highlighted these differences and also investigated relevant perception criteria in terms of psycho-acoustic metrics. However, investigations of differences between different kinds of electric and hybrid electric cars are still rare. The purpose of this paper was to present the distribution of tonal components in today's hybrid/electric vehicles. More specifically, the number of prominent orders, their maximum levels and frequency separation were analyzed for the most critical driving conditions. The study is based upon measurements made on 13 electrified cars on the market.
2015-06-15
Technical Paper
2015-01-2365
Zhaohui Sun, Glen Steyer, Jason Ley
Abstract Alternative powertrains, in particular electric and plug-in hybrids, create a wide range of unique and challenging NVH (noise, vibration & harshness) issues in today's automotive industry. Among the emerging engineering challenges from these powertrains, their acoustic performances become more complicated, partially due to reduced ambient masking noise level and light weight structure. In addition, the move away from conventional displacement engines to electrical drive units (EDU) has created a new array of NVH concerns and dynamics, which are relatively unknown as compared to the aforementioned traditional setups. In this paper, an NVH optimization study will be presented, focusing on four distinct factors in electric drive unit gear mesh source generation and radiation: EDU housing and bearing dynamics, gear geometry, EDU shafting torsional dynamics, and EDU housing structure. The study involves intensive FEA modeling/analyses jointly with physical validation tests.
2015-06-15
Technical Paper
2015-01-2362
Todd Tousignant, Kiran Govindswamy, Mark Stickler, Ming-Ran Lee
Abstract The increasing trend toward electric and hybrid-electric vehicles (HEVs) has created unique challenges for NVH development and refinement. Traditionally, characterization of in-vehicle powertrain noise and vibration has been assessed through standard operating conditions such as fixed gear engine speed sweeps at varied loads. Given the multiple modes of operation which typically exist for HEVs, characterization and source-path analysis of these vehicles can be more complicated than conventional vehicles. In-vehicle NVH assessment of an HEV powertrain requires testing under multiple operating conditions for identification and characterization of the various issues which may be experienced by the driver. Generally, it is necessary to assess issues related to IC engine operation and electric motor operation (running simultaneously with and independent of the IC engine), under both motoring and regeneration conditions.
2015-06-15
Technical Paper
2015-01-2350
Jiantie Zhen, Scott Fredrickson
Abstract Off-highway machine mounting system isolation, especially the cab mounting system, significantly affects the operator comfort by providing damping to the harsh inputs and isolating the structure-borne energy from traveling into the cab. Mounting system isolation performance is decided not only by the isolation component, but also the mounting bracket structure, and should be treated as a system. This paper gives a review of how the mounting system isolates structural energy and the effect of the bracket structure stiffness to the mounting system isolation performance.
2015-06-15
Technical Paper
2015-01-2172
Xuan Li, Bingkui Chen, Yawen Wang, Guohua Sun, Teik Lim
Abstract Cycloid drives are widely used in the in-wheel motor for electric vehicles due to the advantages of large ratio, compact size and light weight. To improve the transmission efficiency and the load capability and reduce the manufacturing cost, a novel cycloid drive with non-pin design for the application in the in-wheel motor is proposed. Firstly, the generation of the gear pair is presented based on the gearing of theory. Secondly, the meshing characteristics, such as the contact zones, curvature difference, contact ratio and sliding coefficients are derived for performance evaluation. Then, the loaded tooth contact analysis (LTCA) is performed by establishing a mathematical model based on the Hertz contact theory to calculate the contact stress and deformation.
2015-06-15
Journal Article
2015-01-2196
Farokh Kavarana, Scott Fritz, John DeYoung
Abstract Recent trends in vehicle light-weighting and tire design requirements have created an increased awareness to tire flat-spotting. Tire flat-spotting occurs when tires remain in a loaded condition without rolling for an extended period of time. Tire flat-spotting can either be temporary or permanent depending on the length of storage and other environmental factors. Tire non-uniformity caused due to flat-spots often induces shake and shimmy (back and forth oscillation of steering wheel) vibration in vehicles due to increased tire-wheel force variation input into the chassis. This can result in increased warranty costs for OEMs (Original Equipment Manufacturers) as well as customer dissatisfaction exhibited in third party quality surveys like the annual J. D. Power IQS (Initial Quality Survey).
Viewing 1 to 30 of 18401