Criteria

Text:
Display:

Results

Viewing 1 to 30 of 19110
2016-06-15
Technical Paper
2016-01-1803
Hannes Frank, Claus-Dieter Munz
Avoiding narrowband components in the acoustic spectrum is one of the most critical objectives in the automotive aeroacoustic optimization process. The underlying physical mechanisms are not completely understood. In a preceding numerical and experimental investigation, we performed large eddy simulations of an early-development stage realistic side-view mirror, where tonal noise was captured and the principle mechanisms were identified. In this contribution, we present simulations on a simplified two-dimensional geometry that is based on these findings. It is shown that the basic flow topology relevant for tonal noise generation on the original side-view mirror as well as the tonal noise source is reproduced in the 2D case. Furthermore, we present comparisons with measurements and the necessity and influence of a splitter plate downstream of the 2D body to avoid large scale vortex shedding.
2016-06-15
Technical Paper
2016-01-1807
Olga Roditcheva, Lennart Carl Lofdahl, Simone Sebben, Pär Harling cEng, Holger Bernhardsson
Abstract This paper presents an experimental study of aeroacoustical sound sources generated by the turbulent flow around the side mirror of a Volvo V70. Measurements were carried out at the Volvo Cars aerodynamical wind tunnel (PVT) and at the aeroacoustical wind tunnel of Stuttgart University (FKFS). Several different measurement techniques were applied in both tunnels and the results were compared to each other. The configurations considered here were: side mirror with a cord and without the cord. The results discussed in this paper include intensity probe measurements in the flow around the side mirror, sound source localization with beamforming technique using a three-dimensional spherical array as well as standard measurements inside the car with an artificial head. This experimental study focused on understanding the differences between testing at the PVT and FKFS.
2016-06-15
Technical Paper
2016-01-1839
Emar Vegt
Abstract The quiet nature of hybrid and electric vehicles has triggered developments in research, vehicle manufacturing and legal requirements. Currently, three countries require fitting an Approaching Vehicle Alerting System (AVAS) to every new car capable of driving without a combustion engine. Various other geographical areas and groups are in the process of specifying new legal requirements. In this paper, the design challenges in the on-going process of designing the sound for quiet cars are discussed. A proposal is issued on how to achieve the optimum combination of safety, environmental noise, subjective sound character and technical realisation in an iterative sound design process. The proposed sound consists of two layers: the first layer contains tonal components with their pitch rising along with vehicle speed in order to ensure recognisability and an indication of speed.
2016-06-15
Technical Paper
2016-01-1837
Stephan Brandl, Werner Biermayer, Bernhard Graf, Thomas Resch
Abstract Due to more stringent emission regulation, especially plug-in hybrid vehicles have an increased attractiveness for OEMs to reduce OEM’s CO2 fleet emission. Generally, hybrid vehicles have a much higher complexity than conventional vehicles. This gives an additional degree of freedom for the development but also increases the number of potential NVH topics dramatically. Therefore, the role of frontloading and early prototype testing is getting even higher importance than in standard developments. Current hybrid vehicles on the market are mainly ICE vehicles with electric boosting or starting functionality only. This however will not be sufficient to fulfill the OEM’s CO2 fleet emission requirements. Future hybrid vehicles will have much higher electrical capabilities and drive much more in pure electric modes. Therefore, the more frequent change between the different driving modes and the related mode transitions will lead to a more complex interior NVH situation.
2016-06-15
Technical Paper
2016-01-1841
Peter R. Hooper
Powertrain system duplication for hybrid electric vehicles and range-extenders presents serious cost challenges. Cost increase can be mitigated by reducing the number of cylinders but this usually has a negative impact on noise, vibration and harshness (NVH) of the vehicle system. This paper considers a novel form of two-stroke cycle engine offering potential for low emissions, reduced production cost and high potential vehicle efficiency. The engine uses segregated pump charging via the use of stepped pistons offering potential for low emissions. Installation as a power plant for automotive hybrid electric vehicles or as a range-extender for electric vehicles could present a low mass solution addressing the drive for vehicle fleet CO2 reduction. Operation on the two-stroke cycle enables NVH advantages over comparable four-stroke cycle units, however the durability of conventional crankcase scavenged engines can present significant challenges.
2016-06-15
Technical Paper
2016-01-1845
Xueji Zhang, ZhongZhe Dong, Martin Hromcik, Kristian Hengster-Movric, Cassio Faria, Herman D. Van der Auweraer, Wim Desmet
Active vibration reduction for lightweight structures has attracted more and more attention in automotive industries. In this paper, reduced-order controllers are designed based on H∞ techniques to realize vibration reduction. A finite element model of piezo-based smart structure is constructed from which a nominal model containing 5 modes and validation model containing 10 modes are extracted. A mixed-sensitivity robust H∞ controller is firstly designed based on the nominal structural model. Considering the ease of controller deployment, an order reduction for the controller is then exploited using balanced truncation method. The effectiveness of the reduced-order controller is finally verified on the validation model via system simulations.
2016-06-15
Technical Paper
2016-01-1851
Arnaud Duval, Minh Tan Hoang, Valérie Marcel, Ludovic Dejaeger
Abstract The noise treatments weight reduction strategy, which consists in combining broadband absorption and insulation acoustic properties in order to reduce the weight of barriers, depends strongly on surface to volume ratio of the absorbing layers in the reception cavity. Indeed, lightweight technologies like the now classical Absorber /Barrier /Absorber layup are extremely efficient behind the Instrument Panel of a vehicle, but most of the time disappointing when applied as floor insulator behind the carpet. This work aims at showing that a minimum of 20 mm equivalent “shoddy” standard cotton felt absorption is requested for a floor carpet insulator, in order to be able to reduce the weight of barriers. This means that a pure absorbing system that would destroy completely the insulation properties and slopes can only work, if the noise sources are extremely low in this specific area, which is seldom the case even at the rear footwells location.
2016-06-15
Technical Paper
2016-01-1850
Christian Thomas, Nouredine Atalla
In passenger aircraft the most important noise control treatment is the primary insulation attached to the fuselage. Next to its acoustic properties the primary insulation main purpose is the thermal insulation and the minimization of condensed water. In general it consists of fibrous materials like glass wool wrapped in a thin foil. Due to stringent flame, smoke and toxicity requirements the amount of available materials is limited. Furthermore the amount of material installed in aircraft per year is much smaller compared to needs in the automotive industry. Therefore the best lay-up of the available materials is needed in terms of acoustics. This paper presents a tool for numerical optimization of the sound insulation package. To find an improved insulation the simulation tool is used in interaction with a measurement database. The databank is constructed from aircraft grade materials such as fibrous materials, foams, resistive screens and impervious heavy layers.
2016-06-15
Technical Paper
2016-01-1835
Albert Albers, Fabian Schille, Matthias Behrendt
Abstract In terms of customer requirements, driving comfort is an important evaluation criterion. Regarding hybrid electric vehicles (HEVs), maneuver-based measurements are necessary to analyze this comfort characteristic [1]. Such measurements can be performed on acoustic roller test benches, yielding time efficient and reproducible results. Due to full hybrid vehicles’ various operation modes, new noise and vibration phenomena can occur. The Noise Vibration Harshness (NVH) performance of such vehicles can be influenced by transient powertrain vibrations e.g. by the starting and stopping of the internal combustion engine in different driving conditions. The paper at hand shows a methodical procedure to measure and analyze the NVH of HEVs in different driving conditions.
2016-06-15
Technical Paper
2016-01-1776
Alexander Rabofsky, Alexander Koeck, Martin Mittermaier
Abstract Lightweight vehicle design causes special demands for functional NVH design. The reduction of weight by reducing material thickness, enabled by new alloys, the combination of materials and new materials increases the sensitivity of a vehicle body to the vibrational and acoustical response of external forces like powertrain or road and wind excitation. To be able to fully raise lightweight potentials design has to be driven closer to functional boundaries, putting higher demands on the accuracy of the prediction by simulation. For a robust design a very broad view on several loadcases is needed to make sure that by optimization on one target no other target is violated. In this paper, optimization strategies for complex NVH load-cases should be investigated in detail. In reality, load-cases, excitations as well as boundary conditions are very often complex and complicated.
2016-06-15
Technical Paper
2016-01-1804
Stefan Becker, Katrin Nusser, Marco Oswald
Abstract Aim of the ongoing development of passenger cars is to predict the interior acoustics early in the development process. A significant noise component results from the flow phenomena in the area of the side window. Wind noise is a physical problem that involves the three complicated aspects each governed by different physics: The complex turbulent flow field in the wake of the a-pillar and the side mirror is characterized by velocity and pressure fluctuations. The flow field generates sound which is transmitted into the passenger cabin. In addition to that, it excites the structure, resulting in a radiation of structure-borne noise into the interior of the car. Therefore, the sound generation is governed by fluid dynamics of the air flow. The sound transmission through the structure due to vibrations is determined by structural mechanics of the body structure. The sound propagation inside the cabin is influenced by interior room acoustics.
2016-05-01
Journal Article
2015-01-9144
Marc-Olivier Lacerte, Gabriel Pouliot, Jean-Sébastien Plante, Philippe Micheau
Electric Vehicles (EVs) with single-ratio gearbox provide high levels of smoothness, but using multi-speed gearbox can provide significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. In particular, Automated Manual Transmissions (AMTs) have characteristics of smooth shifts without torque interruption when coupled to a torque bypass clutch. However, conventional friction clutches are not best suited as torque bypass clutches because of their limited controllability and because large amount of heat must be dissipated to slow down the motor during gearshifts. This paper studies the feasibility of a seamless AMT architecture for EVs and Hybrid Electric Vehicles (HEVs) using an eddy current torque bypass clutch that is highly controllable, robust, low cost, and has no wearable parts.
2016-05-01
Journal Article
2015-01-9132
Husain Kanchwala, Harutoshi Ogai
Abstract Japan is suffering from the problem of an ageing society. In Kitakyushu city more than a quarter of people are aged above 65 years. The roads in this region are narrow with steep gradient and vulnerable roadbed. A big ratio of elderly people are living on their own. These characteristics make driving unsuitable. The problem is magnified by infrequent public transportation. A need-assessment survey for an autonomous vehicle at a community event suggested the applicability of small electric vehicle Toyota COMS. The vehicle is then equipped with features like automatic driving and platooning. The autonomous drive system is built to develop an intelligent transport system (ITS) using various sensors and actuators. Stereo camera and ultrasonic sensors were used to get a judgment of obstacle. Google earth and GPS were used to generate the target path using the Bezier curve method and optimized route is chosen.
2016-05-01
Journal Article
2015-01-9147
Zhiyun Zhang, Miaohua Huang, Yupu Chen, Shuanglong Zhu
Abstract In the field of Electric Vehicle (EV), what the driver is most concerned with is that whether the value of the battery's capacity is less than the failure threshold because of the degradation. And the failure threshold means instability of the battery, which is of great danger for drives and passengers. So the capacity is an important indicator to monitor the state of health (SOH) of the battery. In laboratory environment, standard performance tests can be carried out to collect a number of related data, which are available for regression prediction in practical application, such as the on-board battery pack. Firstly, we make use of the NASA battery data set to form the observed data sequence for regression prediction. And a practical method is proposed to determine the minimum embedding dimension and get the recurrence formula, with which a capacity model is built.
2016-04-15
Journal Article
2015-01-9020
Emre Sert, Pinar Boyraz
Abstract Studies have shown that the number of road accidents caused by rollover both in Europe and in Turkey is increasing [1]. Therefore, rollover related accidents became the new target of the studies in the field of vehicle dynamics research aiming for both active and passive safety systems. This paper presents a method for optimizing the rear suspension geometry using design of experiment and multibody simulation in order to reduce the risk of rollover. One of the major differences of this study from previous work is that it includes statistical Taguchi method in order to increase the safety margin. Other difference of this study from literature is that it includes all design tools such as model validation, optimization and full vehicle handling and ride comfort tests. Rollover angle of the vehicle was selected as the cost function in the optimization algorithm that also contains roll stiffness and height of the roll center.
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
2016-01-1149
Hanqi Yue, Xintian Lu, Xuesong Li, Bingzhao Gao, Hong Chen
Abstract A novel torque-coupling architecture for hybrid electric vehicles is proposed. The torque-coupling device is based on automated manual transmission (AMT), which is highly efficient and provides six gears for the engine and three gears for each motor to enable the engine and the motors to work at high-efficiency levels in most cases. The proposed power-shift AMT (P-AMT) does not have a hydraulic torque converter and wet clutches, which dampen the driveline shock. Thus, the drivability control of the P-AMT becomes a challenging issue. Accurate engine, motor model and transmission model have been built and the dynamic control of the gear shift process of PAMT in hybrid mode is simulated. The electric motors compensate for the traction loss during the gear shift of the engine.
2016-04-05
Journal Article
2016-01-1168
Dennis Kuhl, Ludwig Brabetz, Mohamed Ayeb
Abstract The development of battery electric vehicle drives comes along with comprehensive and time-consuming finite element methods and extensive measurement campaigns. The drive efficiency has drawn great attention from engineers and customers, because it influences the size of the drive, the cooling measures and the vehicle range. Indirect efficiency acquisition accomplished by comparing inward and outward power, has a low accuracy which arises from a relatively small difference between inward and outward power of highly efficient drives. Therefore the indirect efficiency acquisition is insufficient to evaluate advanced development measures.
2016-04-05
Technical Paper
2016-01-1171
Shota Hirose, Akemi Okawa, Kenji Ishida, Takahiro Misu, Takeshi Tojo
Abstract Electrification of the powertrain to improve vehicle fuel economy is a key technology to achieve strict fuel economy legislation. However, only limited numbers of small class vehicles such as a B segment adopt electric powertrain. This is presumed that cost effectiveness for fuel economy is small and mounting space for additional powertrain is limited. In this paper, the optimum solution of a strong hybrid system suitable for the small vehicles was studied. First, from the viewpoint of maximization of energy efficiency, we compared contributions of engine efficiency and transmission efficiency during mode cycle driving and selected automated manual transmission as a suitable transmission for small vehicles. In comparing the hybrid system function, we determined a motor generator connecting shaft and a necessary motor generator output power for attaining both fuel economy and drivability.
2016-04-05
Technical Paper
2016-01-1170
George Dixon, Thomas Steffen, Richard Stobart
Abstract The TC48 project is developing a state-of-the-art, exceptionally low cost, 48V Plug-in hybrid electric (PHEV) demonstration drivetrain suitable for electrically powered urban driving, hybrid operation, and internal combustion engine powered high speed motoring. This paper explains the motivation for the project, and presents the layout options considered and the rationale by which these were reduced. The vehicle simulation model used to evaluate the layout options is described and discussed. The modelling work was used in order to support and justify the design choices made. The design of the vehicle's control systems is discussed, presenting simulation results. The physical embodiment of the design is not reported in this paper. The paper describes analysis of small vehicles in the marketplace, including aspects of range and cost, leading to the justification for the specification of the TC48 system.
2016-04-05
Journal Article
2016-01-1161
Akira Mori
Abstract In 2007, researchers at the Massachusetts Institute of Technology successfully completed a Wireless Power Transfer (WPT) experiment. Ever since, interest in WPT has been growing. At Toyota, we have been developing the underlying technology of a WPT system. Simultaneously we have been working with regulatory committees to create a standard for WPT. In particular, there are concerns that WPT’s radiated emissions could cause harm to humans and the neighboring electronic equipment. There are many challenges that need to be overcome, but a key concern is understanding WPT’s electromagnetic compatibility (EMI: Electro-Magnetic Interference and EMF: Electro-Magnetic Field). In this paper, we show the technical issues, the evaluation method, and the development status of EMI and EMF on PHVs/EVs when using WPT. For Electromagnetic interference (EMI) performance, we investigated both an open area test site and an electromagnetic anechoic chamber as evaluation environments.
2016-04-05
Journal Article
2016-01-1166
Zifan Liu, Andrej Ivanco, Zoran S. Filipi
Abstract The 48V mild hybrid technology is emerging as a very attractive option for high-volume vehicle electrification. Compared to high-voltage hybrids, the 48V system has a potential of achieving competitive fuel economy with significantly lower incremental costs. While previous studies of 48V mild hybrid systems discussed vehicle configuration, power management strategy and electric machine design, quantitative assessment of fuel economy under real-world conditions remains an open topic. Objectives of this paper are to propose a methodology for categorizing real-world cycles based on driver aggressiveness, and to subsequently analyze the impact of driving patterns on fuel saving potentials with a 48V mild hybrid system. Instead of using the certification test cycles to evaluate the fuel economy, real-world cycles are extracted from 2001-2003 Southern California Household Travel Survey.
2016-04-05
Technical Paper
2016-01-1160
Jonathan Hall, Michael Bassett, Stephen Borman, Tom Lucas, Andrew Whitehead
Abstract Present automobile development is keenly focused on measures to reduce the CO2 output of vehicles. Plug-in hybrid electric vehicles (PHEVs) enable grid electricity, which is clean in tail-pipe emissions terms, to be utilised whilst the on-board electrical storage has sufficient charge. MAHLE Powertrain and Protean have jointly developed a plug-in hybrid demonstrator vehicle based on a C-segment passenger car. The vehicle features Protean’s compact direct drive in-wheel motors with integrated inverters on the rear axle and retains the standard gasoline engine, and manual transmission, on the front axle. To support this one-off prototype, a flexible vehicle control unit has been developed, which is easily re-configurable and adaptable to any hybrid vehicle architecture.
2016-04-05
Technical Paper
2016-01-1156
Yuchi Meng, Patrick Currier
Abstract Hybrid vehicle technology has become widely accepted due to its ability to reduce emissions and energy consumptions over conventional vehicles. Current optimization strategy for a parallel hybrid requires a lot of computational time and relies heavily on the drive cycle to accurately represent the driving conditions in the future. In this paper, a vehicle simulation model and a method to optimize parallel strategy to minimize energy consumption while having a fast solving time and being drive cycle independent is developed. The proposed methodology differs from the widely used dynamic programming approach for optimizing parallel strategy, which relies on accurately representing the actual driving behavior, by using the efficiencies of the engine, electric machines, inverters and the battery to predict the impact of current operating point on the overall powertrain system efficiency.
2016-04-05
Technical Paper
2016-01-1155
Toru Nakamura, Takahiro Misawa, Yusuke Futakuchi, Kensuke Kamichi
Abstract Toyota Motor Corporation (TMC) began a wireless charging field test in February 2014. A wireless charging system was installed at the residences of test subjects with the aim of identifying issues related to convenience and installation in daily usage. The test vehicle was fabricated by installing a wireless charging system into a Prius PHV (Plug-in Hybrid Vehicle). The installed system had the same charging power as the cable charging system used on the base vehicle, and had a charging time of 1.5 hours. A high-frequency 85 kHz power supply and primary coil were produced for the charging infrastructure. To identify differences in charging behavior, the test subjects were asked to use the cable charging system for the first month before changing to the wireless charging system for two months. Data acquisition was performed by an on-board data logger and through interviews with the test subjects.
2016-04-05
Technical Paper
2016-01-1158
Toshiaki Watanabe, Masaya Ishida
Abstract Wireless charging systems for electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) employing the resonant magnetic coupling method and using induction coils have been intensively studied in recent years. Since this method requires kW class high power to be transmitted using resonant magnetic coupling in the high frequency range, it is necessary to pay attention to the leakage of the magnetic field generated by the coil current, and to its influence on surrounding objects, particularly human bodies. Noting that acceptable values for human body exposure to electromagnetic fields have previously been issued by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) as guidelines, we have developed a method for predicting product compliance with those guidelines at the basic design development stage.
2016-04-05
Journal Article
2016-01-1188
Stuart Chubbock, Ralph Clague
Abstract Fuel cells offer a high-efficiency and low-emission alternative to internal combustion engines (ICE) in vehicle applications. The fuel cell is silent, vibration free and zero emissions at point of use which allows the vehicle engineer considerably greater operational flexibility than with an ICE. The engineer is no longer constrained by the need to maintain discrete power levels to minimise noise intrusion, or switch the ‘engine’ off at low vehicle speeds to reduce noise and vibration. This paper presents simulation work comparing the performance of a typical B-segment electric vehicle with either a fuel cell or an ICE range extender over a number of real-world drive cycles. Intelligent Energy’s ‘Gen4’ air cooled fuel cell system is detailed as the fuel cell range extender, a typical 660cc naturally aspirated gasoline engine is considered for comparison.
2016-04-05
Technical Paper
2016-01-1186
Dong Hao, Yongping Hou, Jianping Shen, Liying Ma
Abstract The vehicular fuel cell stack is unavoidably impacted by the vibration in the real-world usage due to the road unevenness. However, effects of vibration on stacks have yet to be completely understood. In this work, the mechanical integrity and gas-tightness of the stack were investigated through a strengthen road vibration test with a duration of 200 h. The excitation signals applied in the vibration test were simulated by the acceleration of the stack, which were previously measured in a vehicle vibration test. The load signals of the vehicle vibration test were iterated through a road simulator from vehicle acceleration signals which were originally sampled in the proving ground. Frequency sweep test was conducted before and after the vibration test. During the vibration test, mechanical structure inspection and pressure maintaining test of the stack were conducted at regular intervals.
2016-04-05
Journal Article
2016-01-1181
Takao Watanabe, Tadashi Fujiyoshi, Akira Murakami
Abstract In the present paper, we introduce a drivetrain system using an electromagnetic coupling for hybrid electric vehicles, and propose a new control concept of vibration torque interception. The electromagnetic coupling is an electric machine that is composed of a pair of rotors, and electromagnetic torque acts mutually between the rotors. In the drivetrain system, the electromagnetic coupling works as a torque transmission device with a rotational-speed-converting function. We demonstrate that, by using this control, the electromagnetic coupling also works as a damping device that intercepts the vibration torque of the internal combustion engine, while transmitting the smooth torque to its drive line. Using a model of a two-inertia resonance system, a control system is designed such that a transfer function representing input-to-output torque is shaped in the frequency domain.
2016-04-05
Journal Article
2016-01-1184
Kyoung-Ku Ha, Chang Ha Lee, Chi Myung Kim, Sae Hoon Kim, Byung Ki Ahn
Abstract The subject of this study is a centrifugal compressor for Fuel Cell Electric Vehicles (FCEV). Recently there is a growing interest in FCEVs since they are considered a realistic solution to environmental regulations for passenger cars to reduce emissions. Water vapor is the only byproduct of a reaction in the Proton Electrolyte Membrane (PEM) fuel cell stack which generates electricity with oxygen from the surrounding air and hydrogen from a fuel tank. Auxiliary systems called Balance of Plant (BOP) serve to provide air and hydrogen to the stack in a correct ratio. The compressor is one of key components of this system because compression of the intake air brings an increase in efficiency and power density of the FCEV. This paper presents the characteristics of a 10 kW class centrifugal compressor with an oil-free bearing system. It consists of a shaft, two airfoil journal bearings and a pair of thrust bearings.
Viewing 1 to 30 of 19110