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2016-04-05
Journal Article
2015-01-9152
André Lundkvist, Arne Nykänen, Roger Johnsson
Abstract Many of the information systems in cars require visual attention, and a way to reduce both visual and cognitive workload could be to use sound. An experiment was designed in order to determine how driving and secondary task performance is affected by the use of information sound signals and their spatial positions. The experiment was performed in a driving simulator utilizing Lane Change Task as a driving scenario in combination with the Surrogate Reference Task as a secondary task. Two different signal sounds with different spatial positions informed the driver when a lane change should be made and when a new secondary task was presented. Driving performance was significantly improved when both signal sounds were presented in front of the driver. No significant effects on secondary task performance were found. It is recommended that signal sounds are placed in front of the driver, when possible, if the goal is to draw attention forward.
2016-04-05
Journal Article
2015-01-9153
André Lundkvist, Arne Nykänen
Abstract The number of advanced driver assistance systems is constantly increasing. Many of the systems require visual attention, and a way to reduce risks associated with inattention could be to use multisensory signals. A driver's main attention is in front of the car, but inattention to surrounding areas beside and behind the car can be a risk. Therefore, there is a need for driver assistance systems capable of directing attention to the sides. In a simulator study, combined visual, auditory and vibrotactile signals for directional attention capture were designed for use in driver assistance systems, such as blind spot information, parking assistance, collision warnings, navigation, lane departure warning etc. An experiment was conducted in order to measure the effects of the use of different sensory modalities on directional attention (left/right) in driver assistance systems.
2016-04-05
Technical Paper
2016-01-1120
Dong Guo, Quan Shi, Peng Yi
Gear drives are widely used in the transmission of many types of vehicles and various gear faults were reported to have different effects on the performance of transmission systems. The psychoacoustics metrics, which are used to represent the human hearing property, are objective indicators of product sound quality performance. Therefore, psychoacoustic analysis of gear noise with gear faults needs to be conducted. In this paper, different types of gear faults are summarized, and three of them, including wear, misalignment and eccentricity, are studied separately in the psychoacoustic analysis of the synthesized noise signal of an example gearbox. The gear noise spectra for the cases with different gear faults are synthesized based on the findings of previous publications, where it shows that the three gear faults can either increase the amplitude at the harmonics of the gear mesh frequency or cause the sideband responses.
2016-04-05
Technical Paper
2016-01-1056
Vikas Kolage, Santosh Madireddy
The heart and soul of any fuel based automobile is its engine, which forms the powerhouse generating energy required for movement. Since its inception, it forms the most crucial part of any vehicle. It is therefore safe to say that necessity driven innovations are aimed at engine and its related components than any other aggregate of an automobile. The laws of physics which provide this power also constraint the applicability of engines in automobiles. Due to the oscillating motion generated inside cylinders, forces of imbalance are prevalent throughout the mechanism. While primary forces are usually done and dealt by placing counterweights on crankshaft, secondary forces are eliminated through various different accepted measures. The elimination of imbalances isn’t enough to reduce the shake of an engine and hence we need Engine Mounts for this purpose. They absorb the vibrations produced and eliminate chances of coupling and superposition.
2016-04-05
Technical Paper
2016-01-1128
Bo Peng, Tao Liu, Sifa Zheng, Xiaomin Lian
Neutral-idle strategy has been applied for years to improve the fuel consumption of automatic transmission cars. The updated demand is the use of expanded slipping control for further improvement of the transmission efficiency. However, there are the cases of vibration issues caused by slip-controlled clutches. This issue is called shudder as typical problem of vehicle vibration. In this research, a special neutral-idle shudder phenomenon is presented. Experimental research is conducted to give an insight view of this phenomenon. Then, vibration signal analysis is performed in details to reveal the mechanism. The analysis reveals that this special shudder is caused by both torsional vibration of the driveline and planar vibration of the powertrain system. A positive feedback loop between those two kinds of vibrations contributes to the creation of this neutral-idle shudder.
2016-04-05
Technical Paper
2016-01-0431
Guangqiang Wu, Huwei WU, Xiang Chen
During the process of vehicle creeping, severe vibro-impacts of unloaded or lightly loaded gear pairs in a manual transmission may occur in the powertrain system due to some nonlinear characteristics. Multi-staged stiffness clutch damper, as a main nonlinear component, could have a great influence on powertrain system torsional vibration performance. So a mass-production passenger sedan is taken as the research subject and the nonlinear characteristics impact of multi-staged stiffness clutch damper for vehicle creeping vibration is investigated by using lumped-parameter modeling method. Firstly, a quasi-transient model of an inline four-cylinder and four-stroke engine, based on measured data of cylinder gas pressure versus crankshaft angle, is derived. Effective output torque is achieved and as the input excitation to the driveline. Secondly, a 12 DOFs (Degrees of Freedom) nonlinear and branched torsional vibration model is established.
2016-04-05
Technical Paper
2016-01-1127
Enrico Galvagno, Guido Ricardo Guercioni, Alessandro Vigliani
This paper presents a methodology for the assessment of the NVH performance of a DCT depending on some transmission design parameters, e.g. torsional backlash in the synchronizers, clutch disk moment of inertia, etc., during low vehicle speed maneuvers. Firstly, a 21-DOFs nonlinear dynamic model of a C-segment passenger car equipped with a DDCT is presented. From the torsional variables computed during simulation, the forces at the bearings that support the transmission shafts are calculated; both the axial and radial component of each bearing force are estimated through the model. It has been noted that an impact between the teeth of two engaging rotating components, e.g. gears and synchronizers, corresponds to an impulse in the simulated forces, which leads to a bearing force time-history characterized by a very rich frequency content. A broad band excitation is therefore applied to the gearbox case thus generating noise and vibration issues.
2016-04-05
Technical Paper
2016-01-1378
TAKANORI IDE, Kentaro TODA, Yasunori Futamura, Tetsuya Sakurai
Efficient method to solve large-scale eigenvalue computation in vibration is presented. NVH(Noise, Vibration and Harshness) performance is an important quality measure of the vehicle. Therefore the reduction of vibration is one of the key considerations of new automatic transmission design. In addition, accelerating product design time is another important issue. Computer Aided Engineering (CAE) is becoming a more important methodology to reduce product design time. However computational time of eigenvalue problem takes a long. We propose parallel eigenvalue computation (Sakurai-Sugiura method) for large-scale eigenvalue problems. This method has a good parallel scalability according to a hierarchical structure of the method. As a demonstrative problem, we consider large-scale eigenvalue computation of the AISIN AW FWD automatic transmission.
2016-04-05
Technical Paper
2016-01-1063
George Nerubenko
Up to 30% of engine noise is delivered by front end pulley combined with torsional vibration damper, and technically it is the main contributor to recorded engine noise level. So the novel solutions in terms of improving the design and performance of torsional vibration damper would help to reduce radically this component of engine noise. The results of dynamical study of patented torsional vibration damper combined with pulley are presented. Design and structure of torsional vibration damper is based on author’s US Patent 7,438,165 having the self-tuning control system for all frequencies in running engine in all operational regimes. Mathematical model has been used for the analysis of the emitting noise of engine having proposed torsional vibration damper. Attention is paid to mitigation of the sound power levels contributing by engine subsystem “end of crankshaft - torsional vibration damper – pulley”.
2016-04-05
Technical Paper
2016-01-0472
Lianhui Wang, Shuming Chen, Dengfeng Wang, Yang Jiang, Jing chen
With the development of modern transportation industry, noise pollution is becoming a serious problem. Thus how to reduce noise becomes a hot topic. The most commonly used method is the use of porous sound absorption materials. There are different ways to predict the sound absorption performance of the materials. One of them is genetic algorithm. It can intuitively find critical information that cannot be found in theory. Genetic algorithm is an excellent simulation method. It acquires the optimal solution by imitating the natural selection and genetic mechanism. Therefore, the solution is more close to the target solution after multiple optimizations. The purpose of the present study is to propose a novel approach applying the genetic algorithm to predict the porous materials' sound absorption properties. In this paper we use the foam as the porous material.
2016-04-05
Technical Paper
2016-01-1058
Naoki Toyama, Takashi Hoshi
This paper reports on technology for suppressing forced vibration of the multiplate wet clutch used in the automatic transmission of recently released hybrid automobiles. This study constructed technology for predicting forced vibration due to the clutch structure by 3-D Simulation model, and estimated the vibration modes that would occur. Next, running modes with severe forced vibration were extracted using a drivetrain torsional vibration by 1-D Simulation model from the engine to the driveshaft and the vibration target values estimated from the body. These results were used to change to a clutch structure that has sufficient margin with respect to the forced vibration targets and to appropriately adjust the running modes. It was then confirmed using an actual vehicle that forced vibration does not occur in the running mode estimated to have the most severe forced vibration.
2016-04-05
Technical Paper
2016-01-1430
Se Jin Park, Murali Subramaniyam, Seoung Eun Kim, Tae Hyun Kim, Hee Su sin, Dong Hag Seo, Hyu Hyeong Nam, Jeong Cheol Lee
Seating comfort is associated with the various factors and one of the principal components of a vehicle environment which can affect passenger’s comfort is vibration. The seat design plays a vital role in the vibration isolation as it is directly in contact with human body. Vibration isolation properties of a seat depend upon its dynamic parameters such as cushion, spring stiffness, and damping of seat suspension. In recent years, automotive seat designers are paying more attention for the improvement of seat cushion properties. This paper provides information about a new automotive seat concept which use double-wall 3D air mat in cushion along with foam cushion. The air-mats base fabrics are interlinked with numerous spacer threads to make a 3D structure. An optimization-based method is used to determine the optimal seat dynamic parameter for cushion (particularly for double-wall 3D air mat) based on minimizing occupant’s body discomfort.
2016-04-05
Technical Paper
2016-01-1348
Kenichi Higuchi, Fumihiko Toyoda, Hirohito Terashima, Shinji Ikeda, Eitaku Nobuyama
There are two design challenges of the flow path switching valve in a three-stage variable discharge oil pump. The first is to obtain the required discharge pressure characteristics and the other is to prevent hydraulic vibration. Therefore, we established technologies to determine the shape of the valve and the valve housing that resolve these two challenges. The technology to obtain the required discharge pressure characteristics solves equations that are statically true, such as the equations for the equilibrium of forces and hydraulic orifice. The hydraulic vibration control technology derives a differential equation that takes transient behavior, including oil elasticity and inertia, into account. Then, the equation is converted to a transfer function that indicates the valve behavior according to the input of oil pressure changes and then the stability criterion is applied to judge whether hydraulic vibration occurs or not.
2016-04-05
Technical Paper
2016-01-1312
Tom Wood
Abstract Consumers demand a higher level of sound quality inside passenger vehicles. The interior acoustic behavior is perceived as a convenience element. There is a clear expectation of higher sound quality throughout all passenger vehicle segments including light commercial vehicles (LCV). NVH concepts and materials must deal with this increase in consumer expectations. At the same time, OEM requirements for NVH components like sound barriers, absorbers, and damping materials are expected to contribute to the reduction in both fuel consumption and CO2 emissions. Damping materials are designed to reduce structureborne noise of a vehicle body. Low frequency noise (<1000 Hz) is caused by vibration transmitted from the road, wheel/suspension, powertrain, and air stream excitation into the vehicle body. Today, damping products are one of the basic NVH measures employed to eliminate disturbing noise by converting vibrational energy into (imperceptible) thermal energy.
2016-04-05
Technical Paper
2016-01-0079
Tomohisa Harada, Yoshiyuki Hattori, Shinya Ito, Mitoshi Fujimoto, Toshikazu Hori
Recently, the electromagnetic interference to an AM radio by the noise generated from a power control unit in an HV has become a serious problem. In order to solve the problem, most of noise countermeasures focus on noise sources and noise propagation paths. On the other hand, a countermeasure in the radio receiver has been also proposed. This method detects the HV noise by using a noise sensor, and then, the noise signal is subtracted from AM radio signal which the noise superimposed. In this paper, a new noise suppression method using the digital signal processing in the AM radio receiver is proposed, which does not need noise sensors. The procedure of the method is as follows: First, a receiving AM radio signal containing HV noises is resolved into the in-phase component and quadrature component of a carrier by applying a quadrature demodulation.
2016-04-05
Technical Paper
2016-01-1302
Junji Yoshida, Koki Tanaka
Operational transfer path analysis (TPA) is one of TPA methods recently developed. This method calculates contributions of reference points, those are typically set close to force input points, to vehicle interior noise by using only operational data. Through operational TPA (OTPA), effective vibration and noise reduction at the vehicle interior could be achieved by carrying out an intensive countermeasure to the high contributing part. However, performing effective countermeasure becomes difficult in case some reference points have similar high contributions by the influence of a large vibration mode. In such a case, obtaining high contributing vibration mode and considering how to reduce the mode is better than trying to find out a highest contributing reference point. In the OTPA, not only the reference point contribution but also additional useful information such as principal component could be calculated.
2016-04-05
Technical Paper
2016-01-1375
Masahiro Ueda, Satoshi Ito, Daichi Suzuki
Good ride comfort performance, which is represented by noise, vibration, harshness, has high solicitation power for customers. These phenomena are a result of vibration caused at the engine/powertrain or from road surfaces, transmitted to cabin. Therefore, for reduction of these vibrations, a large number of rubber parts are used at the attachment point of cabin, such as engine mounting and suspension bushing. In the vehicle development, demands to examine the vehicle performance including rubber parts using CAE, before prototype evaluation, is increasing. For that reason, a rubber material model which can represent dynamic characteristics (amplitude dependence, frequency dependence, etc.) of the rubber parts with high precision is necessary, but it is difficult to perform amplitude dependence and frequency dependence at the same time using the rubber material model implemented by commercial structure analysis solver.
2016-04-05
Technical Paper
2016-01-0443
Han Zhang, Gang Li, Yu Wang, Yuchuan Gu, Xiang Wang, Xuexun Guo
A vehicular hydraulic electrical energy regenerative semi-active suspension(HEERSS) was presented, and its working principle and performance were analyzed. Firstly, configuration and working principle of the HEERSS were described; Secondly, kinetic equation of HEERSS was deduced, and a skyhook controller was designed for HEERSS. The traditional skyhook control strategy should be changed for the characteristic of HEERSS, because the damping force during extension stroke could be controlled, but not in compression stroke. Thirdly, the performance of HEERSS was compared with passive suspension(PS), traditional semi-active suspension(TSS). The simulation results showed that in the vehicle body resonance frequency and tire resonance frequency, the amplitude of suspension index parameters ranked in a descend order were PS, HEERSS and TSS; but in the transition frequency band, the amplitude of suspension index parameters ranked in a descend order were. TSS, HEERSS and PS.
2016-04-05
Technical Paper
2016-01-1432
Alexander Siefert
A particular challenge in the development of passenger cars is within prognosis of the vibration comfort. The range of requirements is broad as the excitation varies between cobblestones up to California roads. A further demand is the driver expectation which is different for a pickup or for a sports car. There exist several approaches for assessing the vibrations of occupants while driving. On the one side the comfort is evaluated by integral quantities as the SEAT value taking into account a weighting based on the human body sensitivity. Another approach is the dimension of perception, developed by BMW, which is similar to psychoacoustics as the frequency range is separated with respect to appearing vibration phenomena. In the centre of all activities is the seat transmissibility in the frequency range, describing the relation between the input at the seat slides and the output at the interface of human body and trim.
2016-04-05
Technical Paper
2016-01-1296
Yuntao Cao, Dengfeng Wang, Tonghang Zhao, Xining Liu, Chao Li, Hangsheng Hou
The source of noise excitation is different between electric and conventional vehicles due to their distinctive power system architecture. This work focuses on an interior noise contribution analysis using a model established base on the noise path analysis principle. The obtained results show that the structural-borne noise from the road excitation acts as a major contributor to the overall interior noise level, and the structural-borne noise from the powertrain system contributes noticeably as well, whereas the contribution from the electric motor and tire is relatively insignificant.
2016-04-05
Technical Paper
2016-01-1307
Yuntao Cao, Dengfeng Wang, Tonghang Zhao, Xining Liu, Yulei He, Hangsheng Hou
A vehicle vibration issue emerged for a hybrid prototype in pure electric mode during low speed driving. This work explains the effort to identify the root course, and the work performed to resolve the issue. Firstly a motor test was performed with moderate acceleration by enforcing a constant torque load. All relevant information was simultaneously recorded, including the vehicle speed, motor rpm, motor voltage and current signals, the vibration of the motor structure and seat track, etc. Secondly analyses were carried out regarding vehicle vibration characteristics and mechanism. It was found that the torque fluctuation from the motor was the root course of the low speed vehicle vibration under pure electric mode. Finally, an optimization was carried out regarding the driving motor control strategy and the motor structure, along with the control measure to reduce the variation of the electric voltage and current.
2016-04-05
Technical Paper
2016-01-1324
Yuntao Cao, Tonghang Zhao, Chao Li, Meng Yang, Hangsheng Hou
The primary noise source of an electric vehicle differs from that of traditional vehicles due to the structural difference in their powertrain systems. Firstly, this work introduces exterior noise test methods for electric vehicles, including a pass-by noise measurement method during acceleration on the proving ground as well as in a semi-anechoic room, and the obtained results base on those two methods from an electric vehicle are compared and analyzed. Secondly, the mechanism of the source, path, and contribution is illustrated, and a model of a path-source-contribution for electric vehicles is established. The model validation is carried out by the correlation of the measured results under real operating conditions and the calculated outcomes. Finally, by using the model, contribution analyses are carried out to identify the primary exterior noise source.
2016-04-05
Technical Paper
2016-01-1317
Peng Wang, Xin Hua, T Wu, David W. Herrin
Insertion loss in one-third or octave bands is widely used in industry to assess the performance of large silencers and mufflers. However, there is no standard procedure for determining the transmission loss in one-third or octave bands using measured data or simulation. In this paper, assuming that the source is broadband, three different approaches to convert the narrowband transmission loss data into one-third and octave bands are proposed. Each method is described in detail. To validate the three proposed approaches, narrowband transmission loss of a simple expansion chamber is converted into one-third and octave bands, and results obtained from the suggested approaches are demonstrated to agree well with one another.
2016-04-05
Technical Paper
2016-01-0101
Carl Arft, Yin-Chen Lu, Jehangir Parvereshi
Oscillators are key components in automotive electronics systems. For example, a typical automotive camera module may have three or more oscillators, providing the clocks for microcontrollers, Ethernet controllers, and video chipsets. These oscillators have historically been built around a quartz crystal resonator connected to an analog sustaining circuit driving the crystal to vibrate at its resonant frequency. However, quartz-based devices suffer from poor performance and reliability in harsh automotive environments. SiTime has developed timing solutions based on silicon micro-electromechanical systems (MEMS) technology that exhibit better electromagnetic noise rejection and better performance under shock and vibration. In this paper, we first discuss the design and manufacturing of the MEMS-based device, with emphasis on the specific design aspects that improve reliability and resilience in harsh automotive environments.
2016-04-05
Technical Paper
2016-01-0478
Yinzhi He, Zhigang Yang, Yigang Wang
The full scale aeroacoustic wind tunnel of Shanghai Automotive Wind Tunnel Center (SAWTC) of Tongji University has been under full operation since 2009 after nearly 5 years construction and commissioning. This facility is designed with nozzle area 27m2 not only for full scale automobile testing of aerodynamics and aeroacoustics, but also for Buses, light trucks, scale train model etc. The maximal wind speed of this wind tunnel can reach 250km/h. One of the highlights is the extremely low background noise of only 61dBA at 160km/h. It is so quiet a wind tunnel first of all in China and contributes very much to the vehicle development of the vehicles marketed in the Chinese market. In this paper, after a short introduction about layout of the full scale aeroacoustic wind tunnel of Tongji University, the special acoustic measures to achieve so low background noise of this wind tunnel are presented as well.
2016-04-05
Technical Paper
2016-01-1295
Atsushi Itoh, ZongGuang wang, Toshikazu Nosaka, Keita Wada
Electric vehicle has quiet in the cabin, but on the other hand, it becomes easy to perceive refrigerant-induced noise in automotive air-conditioning system. In the case of purchasing air-conditioning components from some suppliers separately, it is crucial to verify whether refrigerant-induced noise occurs in system or not before air-conditioning components are assembled. If target noise occurs less frequently, it is difficult to evaluate in a vehicle testing. This paper presents 1D modeling methodology for simulation of refrigerant-induced noise such as self-excitation noise generated by pressure pulsation through thermal expansion valve. A GT-SUITE commercial code was used to develop a refrigerant cycle model, consisting of compressor, condenser, evaporator, thermal expansion valve and connecting pipe network.
2016-04-05
Technical Paper
2016-01-1319
Kimitoshi Tsuji, Katsuhiko Yamamoto
It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration in advance using virtual engine specifications and a virtual vehicle frame. In our former study, we showed the 1D physical power plant model with electrical starter, battery that can predict combustion transient torque, combustion heat energy and fuel efficiency. The simulated result agreed with measured data. For idling stop system, the noise and vibration during start up is important factor for salability of the vehicle. In this paper as an application of the 1D physical power plant model, we will show the result of analysis that is starter shaft resonance and the effect on the engine mount vibration of restarting from idle stop. The power plant was 3.5L 6cyl NA. The power plant model was realized by energy based model using VHDL-AMS. Here, VHDL-AMS is modelling language stored in IEC international standard (IEC61691-6) and can realize multi physics on 1D simulation.
2016-04-05
Technical Paper
2016-01-1057
Masaya Miyazawa, Kei Mochizuki, Kondo Takashi
To achieve lightweight, low friction and fuel efficient engine, the crankshaft is required to be designed lightweight, small-diameter shaft, long stroke. In this case, vibration of the crankshaft is increased by reduction of shaft stiffness. The conventional way of dealing with this increased vibration used to be to add an inertia mass ring or a double mass damper. Such an approach, however, increases weight, making the balance of weight reduction and vibration reduction less readily achieved. This paper reports on a method of reducing crankshaft vibration without increasing weight by tuning the shape of the crankshaft damper pulley hub. The main factors of the crankshaft vibration increase were investigated that it is coupled mode of the crankshaft bending and the crankshaft damper pulley bending. This was ascertained from the crankshaft behavior measurement and the crankshaft vibration contribution analysis.
2016-04-05
Technical Paper
2016-01-1320
Sri Siva Sai Meduri, V Sundaram, Sathish Kumar S
Air Induction system (AIS) provides sufficient and clean air to the engine for its desired combustion thereby enhancing engine performance. The ideal design of AIS also reduces the engine noise heard at snorkel which contributes to the cabin noise. Good acoustic expertise and several tests are required to optimize the design of AIS. Multiple resonators are commonly used in passenger cars to attenuate the noise. This paper emphasize on One Dimensional (1D) approach to optimize the resonators in the AIS to meet the functional requirements. In AIS, the flow happens from the snorkel to the engine air intake whereas the sound propagates in the opposite direction. The unsteady mass flow through the intake valves causes pressure fluctuations in the intake manifold and these propagate to intake orifice and are radiated as noise which is heard at snorkel.
2016-04-05
Technical Paper
2016-01-1311
Tsuyoshi Kanuma, Katsumi Endo, Fumiaki Maruoka, Hiroshi Iijima, Makoto Kawamura, Keisuke Nakazawa, Eiki Yanagawa
Vane type rotary compressor for HAVC system is simple and compact, but may emit noise caused by collision between vanes and cylinder wall. Some study for this chattering noise is already known, and the investigation focused on the noise in association with compressor revolution speed, temperature, suction pressure, and exhaust pressure, and was reported before. This parameter study was not sufficient yet to reveal the whole behavior of the vane movement. To minimize the noise, it is crucial to examine the details of the mechanism of such vane-operating noise by tracing the behavior of the vanes in time series. The vanes move according to the balance between the top side pressure and the back side pressure of a vane. This report describes a developed visualization technique to monitor the motion of the vane under operating conditions. Also a method of measuring pressure affecting the movement of the vanes is discussed. These approaches elucidated the mechanism of vane chattering.
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