Display:

Results

Viewing 151 to 180 of 9380
2016-04-05
Technical Paper
2016-01-1557
Francesco Castellani, Nicola Bartolini, Lorenzo Scappaticci, Davide Astolfi, Matteo Becchetti
Abstract Shock absorber is one of the most relevant sub-systems of the suspension system for a wide range of vehicles. Although a high level of development and tuning has been reached, in order to ensure high safety standards in almost every situation, some dynamic phenomena affecting vehicle handling or NHV (Noise Vibration Harshness) can appear. The aim of present work is to improve a mathematical model using experimental data from a prototype of monotube shock absorber developed for research purposes. The model takes into account all the main features affecting the global performance of the device, such as non-linear behaviour and the presence of hysteresis loops. Actually, the most important parameters are analyzed, such as flow and orifice coefficients of the valves, coefficients of mechanical compliance of the chambers and oil compressibility, dry and viscous friction coefficients.
2016-04-05
Technical Paper
2016-01-0055
Mark Steffka, Cyrous Rostamzadeh
Abstract Automotive systems can generate un-intentional radio frequency energy. The levels of these emissions must be below maximum values set by the Original Equipment Manufacturer (OEM) for customer satisfaction and/or in order to meet governmental requirements. Due to the complexity of electromagnetic coupling mechanisms that can occur on a vehicle, many times it is difficult to measure and identify the noise source(s) without the use of an electromagnetic interference (EMI) receiver or spectrum analyzer (SA). An efficient and effective diagnostic solution can be to use a low-cost portable, battery powered RF detector with wide dynamic range as an alternative for automotive electromagnetic compatibility (EMC) and design engineers to identify, locate, and resolve radio frequency (RF) noise problems. A practical circuit described here can be implemented easily with little RF design knowledge, or experience.
2016-04-05
Technical Paper
2016-01-0087
Fengrong Bi, Teng Ma, Jian Zhang
Abstract This paper reports an investigation of knock detection in spark ignition (SI) engines using EEMD-Hilbert transform based on the engine cylinder block vibration signals. Ensemble Empirical Mode Decomposition (EEMD) was used to de-compose the signal and detect knock characteristic. Hilbert transform was used to analysis the frequency information of knock characteristics. The result shows that for cylinder block vibration signals, the EEMD algorithm could extract the knock characteristic (include light knock), and the Hilbert transform result shows that the instantaneous of knock characteristics concentrate in 5000-10000Hz. At last, the knock window is then determined, based on which a new knock intensity evaluation factor K is proposed, and the results show that, the parameter K is reasonable and effective.
2016-04-05
Technical Paper
2016-01-0249
Balashunmuganathan Vasanth, Kumar Sathish, Murali Govindarajalu, Mohsin Khan
In recent years reducing the automobile HVAC (Heating Ventilation and automobile conditioning) noise inside the vehicle cabin is one of the main criterions for all OEMs to provide comfort level to the passengers. The primary function of the HVAC is to deliver more air to the cabin with less noise generation for various blower speeds. Designing the optimum HVAC with less noise is one of the major challenges for all automotive manufacturers and HVAC suppliers. During the design stage, physical parts are not available and hence the simulation technique helps to evaluate the noise level of HVAC. In this study, a computational 1D (one dimensional) analysis is carried out to compute the airflow noise originated from the HVAC unit and propagated to the passenger cabin. Modeling has been done using unigraphics and the analysis is carried out using the commercial 1D software GT suite.
2016-04-05
Technical Paper
2016-01-0273
Richard DeJong, Se Ge Jung, John Van Baren
Abstract Methods for conducting accelerated vibration fatigue testing of structures, such as MIL-STD-810G, allow for the non-linear scaling of the test time with the inverse of the rms vibration amplitude based on the slope of the material S-N curve obtained from cyclic fatigue tests. The Fatigue Damage Spectrum (FDS) is used as a method to allow for different level scalings at different frequencies in a broadband vibration environment using the relative responses of resonances in the structure. A recent development in industry has been to mix impulses with random excitations to increase the vibration peak levels (as measured by the kurtosis), thereby accelerating the fatigue even more than would occur with a Gaussian excitation. This paper presents results from a study to determine the conditions under which high kurtosis, impulsive excitations actually produce high kurtosis responses in structural resonances thus increasing the level of the FDS.
2016-04-05
Technical Paper
2016-01-0275
Frédéric Kihm, Andrew Halfpenny, Kurt Munson
Abstract Ground vehicle components are designed to withstand the real operational conditions they will experience during their service life. Vibration tests are performed to qualify their endurance. In order to replicate the same failure mechanism as in real conditions, the test specification must be representative of the service loads. The accelerated testing method, based on fatigue damage spectra (FDS), is a process for deriving a synthesized power spectral density (PSD) representing a random stationary Gaussian excitation and applied over a reduced duration. In real life, however, it is common that service loading includes non-Gaussian excitations. The consequences of not using a representative test signal during product validation testing are a higher field failure rate and added warranty costs. The objective of this paper is to describe a method for synthesizing a PSD test specification with a given kurtosis value, which represents a nonstationary non-Gaussian signal.
2016-04-05
Technical Paper
2016-01-1393
Prabhakar Konikineni, V. Sundaram, Kumar Sathish, Sankarasubramanian Thirukkotti
Abstract Fan shroud is one of the critical components in an engine cooling system. It helps in achieving optimum air flow across the heat exchangers. The major challenge is to design a fan shroud which meets noise, vibration and harshness (NVH) requirements without compromising on air flow targets [1]. An improperly designed fan shroud will cause detrimental effects such as undesirable noise and vibration, which will further damage the surrounding components. In current days, multiple simulations and test iterations are carried out in order to optimize its design. The objective of this paper is to provide a design framework to achieve optimized fan shroud that meets NVH requirements in quick turnaround time using Design for Six Sigma (DFSS) approach [2]. The purpose of the Engine cooling system is to maintain the coolant temperature across the vehicle.
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
Abstract 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. 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 that use double-wall 3D air-mat in cushion along with foam cushion in the seat cushion system. To test the developed seat on vibration isolation characteristics, seating comfort, and ride quality experiments have been performed. This research is divided into two parts. At first, the newly developed seat tested on the motion simulator. In study 2, road tests were performed on the national highway. Two tri-axial accelerometers were used to measure acceleration at the foot and hip in two different seats (seat with and without double-wall 3D air-mat).
2016-04-05
Technical Paper
2016-01-1432
Alexander Siefert
Abstract Predicting the vibration comfort is a difficult challenge in seat design. There is a broad range of requirements as the load cases strongly vary, representing different excitation levels, e.g. cobblestones or California roads. Another demand is the driver expectation, which is different for a pickup and a sports car. There are several approaches for assessing the vibrations of occupants while driving. One approach is the evaluation of comfort by integral quantities like 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 occurring vibration phenomena. The seat transmissibility is in the focus of all activities. In the frequency range it defines 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
2016-01-1322
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
2016-01-1321
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
2016-01-1324
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
2016-01-1317
Peng Wang, Xin Hua, T. Wu, David W. Herrin
Abstract 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 investigated. Each method is described in detail. To validate the three different approaches, narrowband transmission loss data of a simple expansion chamber and a large bar silencer is converted into one-third and octave bands, and results obtained from the three approaches are demonstrated to agree well with one another.
2016-04-05
Technical Paper
2016-01-1320
Sri Siva Sai Meduri, V. Sundaram, Sathish Kumar S
Abstract The Air Induction system (AIS) must provide sufficient and clean air to the engine for its desired combustion thus enhancing engine performance. The critical functions which effect the performance are pressure restriction and acoustic performance. The ideal design of AIS effectively 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 engine noise 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
2016-01-1319
Kimitoshi Tsuji, Katsuhiko Yamamoto
Abstract It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration 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 simulation 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 (engine 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. First, an engine model for 3.5L 6cyl NA engine was developed by energy-based model using VHDL-AMS. Here, VHDL-AMS is modeling language registered in IEC international standard (IEC61691-6) to realize multi physics on 1D simulation.
2016-04-05
Technical Paper
2016-01-0871
Sanjoy Biswas, Manish Bakshi, G Shankar, Achintya Mukhopadhyay
Abstract An emissions, combustion noise and performance study were conducted to explore the effects of two different multiple injections strategies on emissions, combustion noise and performances without altering EGR %. The experiments were done on a six cylinder inline CRDI diesel production engine. The aim of this study is to improve performances (brake specific fuel consumption [BSFC], torque) and combustion noise (reduction) using multiple injection strategies without violating emission regulations. The other objective of this carried-out analysis is to examine the influence of different operating parameters (Speed and Load) and main injection timing combined, on same multiple injection strategies (Pilot- main – after {PMA}and Early - pilot- main –after {EPMA}) by means of analyzing emissions/soot, combustion noise and performances data.
2016-04-05
Technical Paper
2016-01-0220
Ban Gu, Xiaohong Yuan
Abstract With great development of thermoelectric exhaust heat recovery technology, more and more attention has been paid to optimization of automotive thermoelectric generators (ATEGs). A lot of work has been done on optimization of flow field and thermal analysis. However, investigation on acoustic optimization is rather limited. In this paper, efforts have been paid to study the acoustic performance of a flat-plate TEG, and the feasibility of integration of automotive exhaust thermoelectric generator with muffler was discussed. The internal configuration of heat exchanger looks like “fishbone”. Four factors have been taken into consideration: the spacing of two fins, angle of the fins, the diameter of inlet and outlet of exchanger; and filling sound absorbing material in heat exchanger chamber. Based on these four factors, acoustic analysis was carried out.
2016-04-05
Technical Paper
2016-01-0218
Balashunmuganathan Vasanth, Kumar Sathish, Mayur Sah
In an automotive air conditioning, aero-acoustic noise originating from HVAC (Heating Ventilation and Air Conditioning) unit is one of the major concerns for the customer satisfaction. “Fan blower excessive noise” is one among the top issues for all automotive manufacturers. In this paper, a 3D computational analysis is carried out for a passenger car HVAC unit to predict the noise originated from the HVAC unit. HVAC modeling is done using uni graphics and ANSA and the analysis is carried out using the commercial CFD software STAR CCM+. The inputs for the analysis are the airflow at HVAC Inlet, blower speed and the pressure drop characteristics of evaporator, filter and heater core. The computational model is done by considering the blower region as MRF (Moving Reference Frame) and the air flow is considered incompressible. DES (Detached Eddy Simulation) model is used to resolve the eddies generated by the turbulent flow.
2016-04-05
Technical Paper
2016-01-0411
Yosuke Akita, Kenji Abe, Yoshihiro Osawa, Yoshitsugu Goto, Yuji Nagasawa, Noboru Sugiura, Satoshi Wakamatsu, Kyoko Kosaka
Abstract If a vehicle is left in a humid environment, the coefficient of friction between the brake pads and discs increases, generating a discomforting noise during braking called brake squeal. It is assumed that this increase in the coefficient of friction in a humid environment is the effect of moisture penetrating between the brake friction surfaces. Therefore, this paper analyzes the factors causing coefficient of friction variation with moisture between the friction surfaces by dynamic observation of these surfaces. The observation was achieved by changing the disc materials from cast iron to borosilicate glass. One side of the glass brake disc was pushed onto the brake pad and the sliding surface was observed from the opposite side by a charge coupled device (CCD) camera. First, a preliminary test was carried out in a dry state using two pad materials with different wear properties to select the appropriate pad for observing the friction surfaces.
2016-04-05
Technical Paper
2016-01-0448
Yuliang Yang, Yu Yang, Ying Sun, Zhihong Dong, Yunquan Zhang
Abstract To improve the vehicle NVH performance and reduce the vibration of the exhaust system, average driving DOF displacement (ADDOFD) and dynamic analysis are used to optimize hanger locations. Based on the finite element model and rigid-flexible coupling model, exhaust system analysis model was established. According to the finite element model of the exhaust system, the free-free modal analysis is carried out, and the position of the hanging point of the exhaust system is optimized by using the ADDOFD method. Furthermore, through the dynamics analysis, the force of each hanger to the body is calculated by the dynamic analysis, then verify the rationality of the hanging position. The combination of the two methods can effectively determine the better NVH performance of the exhaust system with hanger locations in the earlier vehicle development process.
2016-04-05
Technical Paper
2016-01-0439
Tianqi Lv, Peijun Xu, Yunqing Zhang
Abstract The powertrain mounting system (PMS) plays an important role in improving the NVH (Noise, Vibration, Harshness) quality of the vehicle. In all running conditions of a vehicle, the displacements of the powertrain C.G. should be controlled in a prescribed range to avoid interference with other components in the vehicle. The conventional model of PMS is based on vibration theory, considering the rotation angles are small, ignoring the sequence of the rotations. However, the motion of PMS is in 3D space with 3 translational degrees of freedom and 3 rotational degrees of freedom, when the rotation angles are not small, the conventional model of PMS will cause errors. The errors are likely to make powertrain interfering with other components. This paper proposes a rigid body mechanics model of the powertrain mounting system. When the powertrain undergoes a large rotational motion, the rigid body mechanics model can provide more accurate calculation results.
2016-04-05
Technical Paper
2016-01-0440
Li Jie, Wang Wenzhu, Gao Xiong, Zhang Zhenwei
Abstract The ride comfort of heavy trucks is related to many factors, which include vehicle operating scenarios and vehicle structure parameters. An investigation of the influence of different factors on the ride comfort of heavy trucks was conducted. Based on the elastic theory of a uniform Euler-Bernoulli beam with both ends free, a 6 degree of freedom (DOF) half rigid-elastic vibration model of the vertical dynamic response was developed. The rigid-elastic model is more suitable to describe the actual movement of heavy trucks. The DOFs include vertical displacements of the body and each of two axles, the pitch displacement of the body, and the first and second order bending displacements of the body. The root mean square (RMS) values of body accelerations, dynamic deflections and relative dynamic loads form the evaluation index. Based on the rigid-elastic model, the influence of different factors on the ride comfort of heavy trucks is analyzed in the frequency domain.
2016-04-05
Technical Paper
2016-01-0443
Han Zhang, Gang Li, Yu Wang, Yuchuan Gu, Xiang Wang, Xuexun Guo
Abstract 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 indicated that the performance of HEERSS would be compromise between TSS and PS, but the HEERSS could harvest vibration energy which was advanced than TSS and PS.
2016-04-05
Technical Paper
2016-01-0431
Guangqiang Wu, Huwei Wu, Xiang Chen
Abstract The nonlinear characteristics impact of multi-staged stiffness clutch damper on the vehicle creeping is investigated by using the lumped-parameter modeling method as a certain mass-production passenger sedan is taken as the research subject. Firstly, a quasi-transient engine 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 acquired and as the input excitation to the driveline system. Secondly, a 12-DOF (Degree of Freedom) nonlinear and branched powertrain system and vehicle longitudinal dynamics model is established. The differential mechanism characteristics and dynamic tire property based on the LuGre tire model are considered. Then, for a traditional two-staged stiffness clutch damper in consideration of hysteresis characteristics, vehicle powertrain system responses in both the time and frequency domain are obtained.
2016-04-05
Technical Paper
2016-01-0480
Weiguo Zhang, Mark Likich, Mac Lynch, John White
Abstract The noise radiated from the snorkel of an air induction system (AIS) can be a major noise source to the vehicle interior noise. This noise source is typically quantified as the snorkel volume velocity which is directly related to vehicle interior noise through the vehicle noise transfer function. It is important to predict the snorkel volume velocity robustly at the early design stage for the AIS development. Design For Six Sigma (DFSS) is an engineering approach that supports the new product development process. The IDDOV (Identify-Define-Develop-Optimize-Verify) method is a DFSS approach which can be used for creating innovative, low cost and trouble free products on significant short schedules. In this paper, an IDD project which is one type of DFSS project using IDDOV method is presented on developing a robust simulation process to predict the AIS snorkel volume velocity. First, the IDDOV method is overviewed and the innovative tools in each phase of IDDOV are introduced.
2016-04-05
Technical Paper
2016-01-0475
Lingzhi Li, Jun Li, Bingwu Lu, Yingjie Liu, Zhi Zhang, Hailong Cheng, Yan Zhang, Hangsheng Hou
Abstract Excessive wind noise is one of the most complained problems by owners of new vehicles as evidenced by JD Power Initial Quality Study (IQS) in recent years. After the vehicle speed surpasses 100 km/h, wind noise is gradually becoming the dominant noise source. In an effort to reduce aeroacoustic noise level, Beamforming (BF) is a very effective noise source identification technique used during vehicle wind noise development phases. In this work, based on the planar BF methodology, a large semi-circle microphone array is designed in accordance with the desired resolution and dynamic range pertaining to actual noise source distribution on a typical passenger vehicle. Acoustic array calibration and mapping deformation correction are accomplished by multi-point source method, and the Doppler Effect due to wind is corrected by the location calibration method.
2016-04-05
Technical Paper
2016-01-0474
Shukai Yang, Bingwu Lu, Zuokui Sun, Yingjie Liu, Hangsheng Hou
Abstract A low frequency vibration issue around 3.2 Hz occurs during a commercial heavy truck program development process, and it is linked to extremely uncomfortable driving and riding experiences. This work focuses on an analytical effort to resolve the issue by first building a full vehicle MBS (multi-body-system) model, and then carrying out vibration response analyses. The model validation is performed by using full vehicle testing in terms of structural modes and frequency response characteristics. In order to resolve the issue which is excited by tire non-uniformity, the influence of the cab suspension, frame modes, front leaf spring system and rear tandem suspension is analyzed. The root cause of the issue is found to be the poor isolation of the rear tandem suspension system. The analytical optimization effort establishes the resolution measure for the issue.
2016-04-05
Technical Paper
2016-01-0473
Muthukumar Arunachalam, S Arunkumar, PraveenKumar Sampath, Abdul Haiyum, Beverly Katz
Abstract Current generation passenger vehicles are built with several electronic sensors and modules which are required for the functioning of passive safety systems. These sensors and modules are mounted on the vehicle body at locations chosen to meet safety functionality requirements. They are mounted on pillars or even directly on panels based on specific packaging requirements. The body panel or pillar poses local structural resonances and its dynamic behavior can directly affect the functioning of these sensors and modules. Hence a specific inertance performance level at the mounting locations is required for the proper functioning of those sensors and modules. Drive point modal frequency response function (FRF) analysis, at full vehicle model for the frequency range up to 1000 Hz, is performed using finite element method (FEM) and verified against the target level along with test correlation.
2016-04-05
Technical Paper
2016-01-0472
Lianhui Wang, Shuming Chen, Dengfeng Wang, Yang Jiang, Jing Chen
Abstract In recent years, the interior noise of automobile has been becoming a significant problem. In order to reduce the noise, porous materials have been widely applied in automobile manufacturing. In this study, the simulation method and optimal analysis are used to determine the optimum sound absorption of polyurethane foam. The experimental simulation is processed based on the Johnson-Allard model. In the model, the foam adheres to a hard wall. The incident wave is plane wave. The function of the model is to calculate the noise reduction coefficient of polyurethane foam with different thickness, density and porosity. The back propagation neural network coupled with genetic optimization technique is utilized to predict the optimum sound absorption. A developed back propagation neural network model is trained and tested by the simulation data.
2016-04-05
Technical Paper
2016-01-0517
Kentaro Kimura, Ryoji Habuchi, Tetsuya Kono, Tadashi Mori, Kaname Arimizu
Abstract To reduce cabin noise and vehicle weight (for lower fuel consumption), a lightweight soundproofing cover was developed as a countermeasure to sources of noise, using the Biot theory (vibration propagation theory in poroelastic materials). This report also presents the results of its application to a metal belt-type continuously variable transmission (CVT) used in Toyota Motor Corporation’s 2.0L vehicles.
Viewing 151 to 180 of 9380

Filter

Subtopics