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2016-04-05
Journal Article
2016-01-0277
Xingxing Feng, Kaimin Zhuo, Jinglai Wu, Vikas Godara, Yunqing Zhang
Abstract Interval inverse problems can be defined as problems to estimate input through given output, where the input and output are interval numbers. Many problems in engineering can be formulated as inverse problems like vehicle suspension design. Interval metrics, instead of deterministic metrics, are used for the suspension design of a vehicle vibration model with five degrees of freedom. The vibration properties of a vehicle vibration model are described by reasonable intervals and the suspension interval parameters are to be solved. A new interval inverse analysis method, which is a combination of Chebyshev inclusion function and optimization algorithm such as multi-island genetic algorithm, is presented and used for the suspension design of a vehicle vibration model with six conflicting objective functions. The interval design of suspension using such an interval inverse analysis method is shown and validated, and some useful conclusions are reached.
2016-04-05
Journal Article
2016-01-1120
Dong Guo, Quan Shi, Peng Yi
Abstract 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 two of them, including wear and misalignment, 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 two gear faults can either increase the amplitude at the harmonics of the gear mesh frequency or cause the sideband responses.
2016-04-05
Journal Article
2016-01-1307
Yuntao Cao, Dengfeng Wang, Tonghang Zhao, Xining Liu, Yulei He, Hangsheng Hou
Abstract A vehicle vibration issue emerged for a hybrid prototype during low speed driving in EV mode. This work is focused on the effort to identify the root cause and resolve the issue. The endeavor begins by performing a motor test in moderate acceleration with an imposed constant torque load. All relevant information is simultaneously recorded, including vehicle speed, vibration of motor structure and seat track, motor rpm, voltage and current signals, etc. Then analyses are carried out to strive for a better understanding of the vibration characteristics and identify its mechanism. It is found that the torque ripple from the driving motor is the root cause of the low speed vehicle vibration in EV mode, and the torque ripple is found to be induced by the current distortion resulted from the current sensor drift and electromagnetic interference due to high current signals.
2016-04-05
Journal Article
2016-01-1304
Tadayoshi Fukushima, Hitoshi Takagi, Toshio Enomoto, Hiroyuki Sawada, Tomoyuki Kaneda
Abstract Interior noise caused by exterior air flow, or wind noise, is one of the noise-and-vibration phenomena for which a systematic simulation method has been desired for enabling their prediction. One of the main difficulties in simulating wind noise is that, unlike most other noises from the engine or road input, wind noise has not one but two different types of sources, namely, convective and acoustic ones. Therefore, in order to synthesize the interior sound pressure level (SPL), the body sensitivities (interior SPL/outer source level) for both types of sources have to be considered. In particular, sensitivity to the convective input has not been well understood, and hence it has not been determined. Moreover, the high-frequency nature of wind noise (e.g., the main energy range extends up to 4000 Hz) has limited the effective application of CAE for determining body sensitivities, for example, from the side window glass to the occupants’ ears.
2016-04-05
Journal Article
2016-01-1678
Etsuo Katsuyama, Ayana Omae
Abstract Vehicles equipped with in-wheel motors (IWMs) are capable of independent control of the driving force at each wheel. These vehicles can also control the motion of the sprung mass by driving force distribution using the suspension reaction force generated by IWM drive. However, one disadvantage of IWMs is an increase in unsprung mass. This has the effect of increasing vibrations in the 4 to 8 Hz range, which is reported to be uncomfortable to vehicle occupants, thereby reducing ride comfort. This research aimed to improve ride comfort through driving force control. Skyhook damper control is a typical ride comfort control method. Although this control is generally capable of reducing vibration around the resonance frequency of the sprung mass, it also has the trade-off effect of worsening vibration in the targeted mid-frequency 4 to 8 Hz range. This research aimed to improve mid-frequency vibration by identifying the cause of this adverse effect through the equations of motion.
2016-04-05
Journal Article
2016-01-0079
Tomohisa Harada, Yoshiyuki Hattori, Shinya Ito, Mitoshi Fujimoto, Toshikazu Hori
Abstract Recently, the electromagnetic interference in an AM radio by the noise generated from a power control unit (DC-DC converters, inverters) in a hybrid vehicle (HV) has become a serious problem. To solve the problem, most noise suppression methods, for example, use noise filters for noise sources and shield wiring and ferrite cores for noise propagation paths. In this paper, we propose a noise suppression method using the digital signal processing in an AM radio receiver. In this method, first the receiving AM radio signal containing HV noise is quadrature demodulated. Next, a replica signal of the noise is generated by using the noise signal in the quadrature component. Then, the replica signal is subtracted from the AM radio signal containing the noise of the in-phase component. We construct a prototype of the radio receiver system based on this method and demonstrate that the system can reduce the HV noise superimposed on the AM radio signal by more than 20 dB.
2016-04-05
Journal Article
2016-01-0082
Satoru Komatsu, Yoshio Karasawa, Tatsuya Kashiwa, Kenji Taguchi, Suguru Imai
Abstract The suitability of FM radio receivers for automobiles has conventionally been rated by evaluating reception characteristics for broadcast waves in repeated driving tests in specific test environments. The evaluation of sound quality has relied on the auditory judgment due to difficulties to conduct quantitative evaluations by experiments. Thus the method had issues in terms of the reproducibility and objectivity of the evaluations. To address these issues, a two-stage method generating a virtual radio wave environment on a PC was developed. The research further defined the multipath distortion rate, MDr, as an index for the sound quality evaluation of FM receivers, and the findings concerning the suitability of the evaluation of FM terminals for automobiles were reported at the 2015 SAE World Congress.
2016-04-05
Journal Article
2016-01-0101
Carl Arft, Yin-Chen Lu, Jehangir Parvereshi
Abstract 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
2016-01-1296
Yuntao Cao, Dengfeng Wang, Tonghang Zhao, Xining Liu, Chao Li, Hangsheng Hou
Abstract Noise excitation sources are different between electric vehicles and conventional vehicles due to their distinct propulsion system architecture. This work focuses on an interior noise contribution analysis by experimental measurements and synthesis approach using a methodology established based on the principle of noise path analysis. The obtained results show that the structure-borne noise from the tire-road excitation acts as a major contributor to the overall interior noise level, and the structure-borne noise from the power plant system contributes noticeably as well, whereas contributions from the electric motor and tire are relatively insignificant.
2016-04-05
Journal Article
2016-01-1125
Hiromichi Tsuji, Kimihiko Nakano
Abstract This paper presents a study of experimental transfer path contribution with the estimation technique of the projected operational force under CVT clutch lockup operational condition. Since transfer path analysis is conducted with respect to the evaluation location, the forces applied onto the substructures are, therefore, also required to estimate the coherent operational forces. In order to estimate the forces, the coherent inertance matrix, which is the projection of the inertance matrix onto the subspace with respect to the evaluation location, is estimated without measuring it directly. The acceleration responses at the connections of the passive substructure are measured by the excitation at the evaluation location with reciprocity. The proposed technique decomposes the acceleration responses into the output and input element vectors on the subspace. With those vectors, the coherent full inertance matrix considering cross coupling effects is constructed.
2016-04-05
Technical Paper
2016-01-1349
Siddharth Bhupendra Unadkat, Suhas Kangde, Mahalingesh Burkul, Mahesh Badireddy
Abstract In the current scenario, the major thrust is to simulate the customer usage pattern and lab test using virtual simulation methods. Going ahead, prime importance will be to reduce the number of soft tool prototype for all tests which can be predicted in CAE. Automotive door slam test is significantly complex in terms of prediction through simulation. Current work focuses on simulating the slam event and deriving load histories at different mounting locations through dynamic analysis using LSDyna. These extracted load histories are applied to trimmed door Nastran model and modal transient analysis is performed to find the transient stress history. This approach has a significant advantage of less computation time and stress-convergence with Nastran for performing multiple design iterations compared to LSDyna. Good failure correlation is achieved with the test using this approach.
2016-04-05
Technical Paper
2016-01-1057
Masaya Miyazawa, Kei Mochizuki, Kondo Takashi
Abstract 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 therefore reports on how the main factors causing crankshaft vibration to increase in the shaft with reduced stiffness were clarified. Based on that clarification, efforts were made to reduce crankshaft vibration without increasing the weight of the crankshaft system. Measurement and analysis were used to analyze crankshaft vibration during operation.
2016-04-05
Technical Paper
2016-01-1058
Naoki Toyama, Takashi Hoshi
Abstract The subject is technology for damping forced vibration in the multiplate wet clutches used in hybrid vehicle transmissions. As a predictive technique for forced vibration caused by the structure of the clutch, three-dimensional simulation was used in the present study to anticipate the modes of vibration that occur. Next, a one-dimensional simulation was created as a predictive technique for drivetrain torsional vibration from the engine to the driveshaft. The one-dimensional simulation created was used to extract the modes of operation that are severe with regard to forced vibration from target values for vibration anticipated from the vehicle body. The results obtained were used with three-dimensional simulation to change the clutch structure to provide greater latitude with regard to the target for forced vibration.
2016-04-05
Technical Paper
2016-01-1321
Masahiro Fukazawa, Tsuyoshi Murao, Shingo Unigame
Abstract The CAE method to predict the vibration transfer function of the hydraulic engine mount on a vehicle with sufficient precision and calculation time without prototype cars was developed. The transfer function is given in the following steps. First, rubber deformation form under the power train weight loaded must be predicted. It’s obtained by using a reduction model of an engine mount, as a unit, which doesn’t have its fluid sealed inside, with the technique to get the static spring characteristics in a non-linear relationship. Second, Young’s modulus and structural damping coefficient for the deformed rubber must be given. As for these characteristics, ignoring the relations between these values and strain, the constant values are used. This considerably reduces computation time and model size. Next, the reduction model and the fluid model have must be combined to express actual product. In this step, coupled analysis for fluid and structure is used.
2016-04-05
Technical Paper
2016-01-0479
Kuniaki Goto, Takashi Kondo, Masakiyo Takahira, Eiji Umemura, Masashi Komada, Yasuhiko Nishimura
Abstract Generally, pass-by noise levels measured outdoors vary according to the influence of weather conditions, background noise and the driver’s skill. Manufactures, therefore, are trying to reproduce proving ground driving conditions on a chassis dynamometer. The tire noise that occurs on actual road surfaces, however, is difficult to reproduce in indoor tests. In 2016, new pass-by noise regulations (UN R51-03) will take effect in Europe, Japan and other countries. Furthermore, stricter regulations (2dB) will take effect in 2020. In addition to the acceleration runs required under current regulations, UN R51-03 will require constant speed runs. Therefore, an efficient measurement methods are necessary for vehicle development. To solve the above mentioned issues, an indoor evaluation system capable of reproducing the tire noise that occurs on road surfaces has been developed.
2016-04-05
Journal Article
2016-01-0476
Yongchang Du, Yingping Lv, Yujian Wang, Pu Gao
Abstract Brake squeal is a complex dynamics instability issue for automobile industry. Closed-loop coupling model deals with brake squeal from a perspective of structural instability. Friction characteristics between pads and disc rotor play important roles. In this paper, a closed-loop coupling model which incorporates negative friction-velocity slope is presented. Different from other existing models where the interface nodes are coupled through assumed springs, they are connected directly in the presented model. Negative friction slope is taken into account. Relationship between nodes’ frictional forces, relative speeds and brake pressure under equilibrant sliding and vibrating states is analysed. Then repeated nodal coordinate elimination and substructures’ modal coordinate space transformation of system dynamic equation are performed. It shows that the negative friction slope leads to negative damping items in dynamic equation of system.
2016-04-05
Journal Article
2016-01-0477
Pu Gao, Yongchang Du, Yujian Wang, Yingping Lv
Abstract The dynamic properties of disc rotor play important role in the NVH performance of a disc brake system. Disc rotor in general is a centrosymmetric structure. It has many repeated-root modes within the interested frequency range and they may have significant influence on squeal occurrence. A pair of repeated-root modes is in nature one vibration mode. However, in current complex eigenvalue analysis model and relevant analysis methods, repeated-root modes are processed separately. This may lead to contradictory result. This paper presents methods to deal with repeated-root modes in substructure modal composition (SMC) analysis to avoid the contradiction. Through curve-fitting technique, the modal shape coefficients of repeated-root modes are expressed in an identical formula. This formula is used in SMC analysis to obtain an integrated SMC value to represent the total influence of two repeated-root modes.
2016-04-05
Journal Article
2016-01-1122
Hyungsouk Kang, TaeYoung Chung, Hyeongcheol Lee, Hyungbin Ihm
Abstract Pressure variation during engine combustion generates torque fluctuation that is delivered through the driveline. Torque fluctuation delivered to the tire shakes the vehicle body and causes the body components to vibrate, resulting in booming noise. HKMC (Hyundai Kia Motor Company)’s TMED (Transmission Mounted Electric Device) type generates booming noises due to increased weight from the addition of customized hybrid parts and the absence of a torque converter. Some of the improvements needed to overcome this weakness include reducing the torsion-damper stiffness, adding dynamic dampers, and moving the operation point of the engine from the optimized point. These modifications have some potential negative impacts such as increased cost and sacrificed fuel economy. Here, we introduce a method of reducing lock-up booming noise in an HEV at low engine speed.
2016-04-05
Journal Article
2016-01-1298
Shukai Yang, Zuokui Sun, Yingjie Liu, Bingwu Lu, Tao Liu, Hangsheng Hou
Abstract This work carries out complex modal analyses and optimizations to resolve an 1800 Hz front brake squeal issue encountered in a vehicle program development phase. The stability theory of complex modes for brake squeal simulation is briefly explained. A brake system finite element model is constructed, and the model is validated by the measurement in accordance with the SAE 2521 procedure. The key parameters for evaluating the stability of the brake system complex modes are determined. The modal contributions of relevant components to unstable modes are analyzed and ranked. Finally, in order to resolve the squeal issue, the design improvements of rotor, caliper and pad are proposed and numerical simulations are carried out. The obtained results demonstrate that the optimized rotor and pad design can alleviate the squeal issue significantly while the optimized clipper design could essentially eliminate the squeal issue.
2016-04-05
Journal Article
2016-01-1299
Robert S. Ballinger
Abstract The complex eigenvalue analysis has been used by the brake research community to study friction-induced squeal in automotive disk brake assemblies. The analysis process uses a nonlinear static pre-stressed normal modes analysis simulation sequence followed by a complex eigenvalue extraction algorithm to determine the dynamic instabilities. When brake hardware exists, good correlation between analysis results and experimental data can be obtained. Consequently, complex eigenvalue analysis can be a valuable method in an effort to understand brake components that might have a propensity to influence the noise behavior of a brake system. However, when hardware does not exist and the complex eigenvalue method is asked to be predictive, it becomes a difficult, if not impossible task. This paper will focus on some of the reasons the complex eigenvalue analysis method is not a reliable predictor of friction-induced squeal in automotive disk brake assemblies.
2016-04-05
Journal Article
2016-01-1310
Yitian Zhang, David W. Herrin, T. Wu, Xin Hua
Abstract Prior research on assessing multiple inlet and outlet mufflers is limited, and only recently have researchers begun to consider suitable metrics for multiple inlet and outlet mufflers. In this paper, transmission loss and insertion loss are defined for multiple inlet and outlet mufflers using a superposition method that can be extended to any m-inlet n-outlet muffler. Transmission loss is determined assuming that the sources and terminations are anechoic. On the other hand, insertion loss considers reflections. For both metrics, the amplitude and phase relationship between the sources should be known a priori. This paper explains both metrics, and measurement of transmission and insertion loss are demonstrated for a 2-inlet 2-outlet muffler with good agreement.
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
Journal Article
2016-01-1316
Vincent Rovedatti, Jacob Milhorn, Richard DeJong, Gordon Ebbitt
Abstract A 1/4 scale model vehicle profile has been tested in a wind tunnel with speeds up to 360 km/h. In order to simulate the free field flow over the vehicle, the top surface of the wind tunnel is contoured. A CFD simulation of the free field flow at various speeds is used to identify the desired top streamline. Then the boundary layer growth on the top surface is calculated and the top contour is adjusted accordingly. Since this contour changes very little with flow speeds of interest, an average contour is used for a fixed top surface of the wind tunnel. Pressure drop measurements are used to verify the flow similarity to the CFD model. Wind noise measurements using surface mounted pressure transducer arrays are used to determine the acoustic loads on the vehicle surfaces.
2016-04-05
Journal Article
2016-01-1315
Yongchang Du, Yingping Lv, Yujian Wang, Pu Gao
Abstract Closed-loop coupling model, based on complex eigenvalue analysis, is one of the most popular and effective methods for brake squeal analysis. In the model, imaginary coupling springs are used to represent the normal contacting force between coupled nodes. Unfortunately, the physical meaning of these coupling springs was seldom discussed and there’s no systematic method to determine the value of spring stiffness. Realizing this problem, this paper, based on finite element model and modal synthesis technique, develops a new closed-loop coupling disc brake squeal model without introducing imaginary coupling springs. Different from the traditional model where two nodes at coupling interface are connected through a spring, these node-pairs in the new model are assumed to remain in tight contact during vibration. Details of the model, including force analysis, coordinate reduction and transformation and complex eigenvalue decomposition are given in this paper.
2016-04-05
Technical Paper
2016-01-1063
George Nerubenko
Abstract 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
2016-01-1325
Masanori Watanabe, Yosuke Tanabe, Naoki Yoneya
Abstract We have developed an excitation source identification system that can distinguish excitation sources on a sub-assembly level (around 30mm) for vehicle components by combining a measurement and a timing analysis. Therefore, noise and vibration problems can be solved at an early stage of development and the development period can be shortened. This system is composed of measurement, control, modeling, and excitation source identification parts. The measurement and the excitation source identification parts are the main topics of this paper. In the measurement part, multiple physical quantities can be measured in multi-channel (noise and vibration: 48ch, general purpose: 64ch), and these time data can be analyzed by using a high-resolution signal analysis (Instantaneous Frequency Analysis (IFA)) that we developed.
2016-04-05
Technical Paper
2016-01-1322
Tonghang Zhao, Xining Liu, Yuntao Cao, Chao Li, Hangsheng Hou
Abstract A hybrid electric vehicle (HEV) will start the engine which drives its motor to charge the battery even at idle whenever the battery power is detected to be insufficient. The activation of idle battery charging could lead to serious NVH problems if powertrain parameters are not designed or calibrated properly. This work is focused on a noise issue encountered during idle charging for a specific prototype vehicle, and investigates control strategies to contain the noise level. Based on basic principles of automobile vibration and noise control along with the specific characteristics of the hybrid vehicle architecture, this work analyzes and elucidates methods of the engine idle charging noise control from the perspectives of powertrain modal alignment, idle speed optimization, and electric motor control algorithm.
2016-04-05
Technical Paper
2016-01-1324
Yuntao Cao, Tonghang Zhao, Chao Li, Meng Yang, Hangsheng Hou
Abstract The primary noise sources of electric vehicles differ from that of traditional vehicles due to the fundamental differences in their powertrain architecture. In this work, some exterior noise test methods for electric vehicles are briefly introduced first, which include a pass-by noise measurement method during acceleration on the proving ground as well as a similar measurement in a semi-anechoic room. The obtained results based on those two methods from a production electric vehicle are compared and analyzed. Then the mechanism of the source, path, and contribution is illustrated, and a model of path-source-contribution for electric vehicles is established. The model validation is subsequently carried out by correlating the calculated outcomes with the measured results under real operating conditions. Finally, by using the model, contribution analyses are carried out to identify the primary exterior noise sources.
2016-04-05
Technical Paper
2016-01-1312
Tom Wood
Abstract Light weighting vehicle acoustic components and improving the performance level of sound abatement treatments is becoming more important to automotive manufacturers due to increased fuel economy requirements established by the Corporate Average Fuel Economy - (CAFE) standards [1], and the consumer’s demand for ever improving sound quality inside the vehicle cabin. In tests conducted by Ricardo Inc. for the Aluminum Association Inc., a 2008 report estimates that for every 45 kg of mass removed from passenger vehicles and light weight commercial vehicles (LCV) up to a 1 percent increase in fuel mileage can be achieved [2]. Automotive OEM’s expect that sound abatement products, sound barriers, absorbers, and damping materials contribute to this reduction in vehicle weight.
2016-04-05
Technical Paper
2016-01-1552
Renato Galluzzi, Andrea Tonoli, Nicola Amati, Gabriele Curcuruto, Piero Conti, Giordano Greco, Andrea Nepote
Abstract The development of suspension systems has seen substantial improvements in the last years due to the use of variable dampers. Furthermore, the efficiency increase in the subsystems within the automotive chassis has led to the use of regenerative solutions, in which electric machines can be employed as generators to recover part of the energy otherwise dissipated. However, the harvesting capability of regenerative suspensions is often limited by friction and inertial phenomena. The former ones waste mechanical energy into heat, while the latter ones hamper the shock absorption by locking the suspension when subject to dynamic excitation. Besides a suitable design and sizing of components, recent research works highlight the use of the so-called motion rectifier to improve energy recovery by constraining the motion of the electric motor to a single sense of rotation.
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