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2017-04-11
Journal Article
2017-01-9625
Souhir Tounsi
Abstract In this paper, we present a design and control methodology of an innovated structure of switching synchronous motor. This control strategy is based on the pulse width modulation technique imposing currents sum of a continuous value and a value having a shape varying in phase opposition with respect to the variation of the inductances. This control technology can greatly reduce vibration of the entire system due to the strong fluctuation of the torque developed by the engine, generally characterizing switching synchronous motors. A systemic design and modelling program is developed. This program is validated following the implementation and the simulation of the control model in the simulation environment Matlab-Simulink. Simulation results are with good scientific level and encourage subsequently the industrialization of the global system.
2017-03-28
Technical Paper
2017-01-1052
Paul Zeng, Vincent Solferino, Mark Stickler
Engine ticking noise is one of the key failure modes in today’s direct injection (DI) engines. High ticking noise results in high Things Gone Wrong (TGW) index, which negatively affects customer satisfaction. In this paper, the root cause of the ticking noise from DI injector in direct mounting will be presented. Design principle such as injector impact force to cylinder head and DI injector isolator design with 2 stage stiffness is proposed.
2017-03-28
Technical Paper
2017-01-0172
Suhas Venkatappa, Manfred Koberstein, Zhengyu Liu
Due to regulations related to global warming, the auto industry is transitioning to the use of a new refrigerant R1234yf in many markets/regions. This transition to the new refrigerant was considered to be a minor development effort with main focus on improved sealing, improving cooling capacity with adding content such as Internal Heat Exchanger (IHX) to recoup the lower cooling efficiency of R1234yf compared to R134a. There were no redesigns of major refrigerant system components expected with the introduction of R1234yf. The actual implementation of this refrigerant has proven to be more challenging due to several NVH issues. Some of the challenges related to NVH are driven by the differences in refrigerant characteristics – mass flow rate, velocity of sound in refrigerant.
2017-03-28
Technical Paper
2017-01-0376
Jianyong Liang, Jonathan Powers, Scott Stevens, Behrooz Shahidi
While Advanced High Strength Steels (AHSS) and next generation steel grades offer improved crash safety and reduced weight for vehicles, the global stiffness and NVH performance are often compromised due to reduced material thickness. This paper discusses an advanced method of evaluating the joint effectiveness on contribution to global stiffness and NVH performance of vehicles. A stiffness contribution ratio is proposed initiatively in this research, which evaluates the current contribution of the joints to the global stiffness and NVH performance of vehicles. Another parameter, joint effectiveness factor, has been used by Ford Motor Company to study the potential of each joint on enhancing the global stiffness. The critical joints to enhance the vehicle stiffness and NVH performance can be identified based on above two parameters, and design changes be made to those critical joints to improve the vehicle performance.
2017-03-28
Technical Paper
2017-01-1553
Min Kyoo Kang, Jin Hong Kim, HyuckJin Oh, Wookjin Jang, Sangwoo Lee, Young Hwan Lee
This paper presents a transient nonlinear vibration analysis of a full-vehicle model. The full-vehicle model consists of a powertrain model, a trimmed body, a drive line, and front and rear suspensions with tires, and is driven by combustion forces and runs on a road surface. The fundamental purpose of the transient nonlinear full-vehicle simulation is to replicate customer’s experience in driving situation in the time domain and to understand real-time phenomena. By performing time-domain simulation, it is possible to capture nonlinear behavior of a vehicle such as preloads due to gravitational force, large deformation, and material nonlinearity which cannot be properly considered in the conventional steady state analysis due to intrinsic linearization process. In constructing a full-vehicle, validation process is essential. Validation process is applied with respect to the assembling sequence.
2017-03-28
Technical Paper
2017-01-0443
Yong Hyun Nam, Gwansik Yoon
The sound induced by a closing door is determined by the various components like door latch, door module, door glass installed within the door area. The key components vibrate due to the force from the closing door, and the combined vibration caused by the components determines the sound from the door. In particular, when the door is closed with the door glass down, the vibration and noise of the door glass are louder than those of any other component; this is called door glass rattle - attributed to the loss of the door glass support point. This study not only evaluates the rattle influence level of a door glass support but also introduces an approach to reduce glass rattle noise by using sealing components. 1. Study on Minimization of Vibration A jig was constructed to evaluate the level of influence of the rattle of a door glass support.
2017-03-28
Technical Paper
2017-01-1226
Nurani Chandrasekhar, Chun Tang, Natee Limsuwan, Joel Hetrick, Jacob Krizan, Zhichun Ma, Wei Wu
Noise and Vibration signature of an electric machine is an outcome of complex interaction between various source level disturbances like torque ripple and radial magnetic force and the surrounding structure to which the motor is attached. These can be radiated directly from the motor housing and also can be transmitted through the structural attachments (stator bolts, mounts etc.). The stator excitation current is not perfectly sinusoidal but contains different levels of harmonics. Harmonics impact Torque ripple, which in turn could translate into undesirable Motor noise. This paper addresses the impact of torque ripple on Motor whine noise. In this work, the electric machine torque ripple was computed based on the stator current that was measured during Motor dyno testing at prescribed torque and speed levels. The Motor NVH under specific torque levels was measured through testing in an anechoic transmission dynamometer cell.
2017-03-28
Technical Paper
2017-01-1136
Jack S.P. Liu, Natalie Remisoski, Javed Iqbal, Robert Egenolf
Automotive vehicles equipped with Cardan joints may experience a low frequency vehicle launch shudder vibration (5-30Hz) and a high frequency driveline moan vibration (80-200Hz) under operated angles and speeds. The Cardan joint introduces a 2nd order driveshaft speed variation and a 4th order joint articulation torque (JAT) causing the vehicle shudder and moan NVH issues. Research on the Cardan joint induced low frequency vehicle shudder using MBS method has been attempted. A comprehensive MBS method to predict the Cardan joint induced high frequency driveline moan vibration is yet to be developed. This paper presents a hybrid Multi-Body System (MBS) and FEA approach to predict the Cardan joint induced high frequency driveshaft moan vibration. The CAE method considers the elastically coupled driveshaft bending and engine block vibration due to Cardan joint excitation. Detailed driveshaft, joints, slip mechanism, differential, axle and wheel were modeled using a MBS modeling tool.
2017-03-28
Technical Paper
2017-01-1311
Suman Mishra, Nagesh Gummadi, Lloyd Bozzi, Neil Vaughn, Rob Higley
Air rush noise is exhaust gas driven flow induced noise in the frequency range of 500-6500 Hz. It is very essential to understand the flow physics of exhaust gases with in the mufflers in order to identify any counter measures that can attenuate this error state. This study is aimed at predicting the flow physics and hence of air rush noise of exhaust mufflers in the aforementioned frequency range at a typical exhaust flow rate and temperature. The study is performed on 2 different muffler designs which show a significant air rush noise level difference when tested on the vehicle. The transient computational study was performed using DES with 2nd order spatial discretization and 2nd order implicit scheme for temporal discretization in StarCCM+. To compare with test data, a special flow test stand is designed so that all high and low frequency contents emanating from the engine are attenuated before the flow enters the test part.
2017-03-28
Technical Paper
2017-01-0405
Tianqi Lv, Xingxing Feng, Peijun Xu, Yunqing Zhang
Several constitutive models which capture the amplitude and frequency dependency of filled elastomers are implemented for the conventional engine mounts of automotive powertrain mounting system (PMS). Firstly, a multibody dynamic model of a light duty truck is proposed, which includes 6 degrees of freedom (DOFs) for the PMS. Secondly, several constitutive models for filled elastomers are implemented for the engine mounts of the PMS, including nonlinear elastic model, frictional derivative viscoelastic model, general Maxwell chains, Coulomb-type friction, Berg’s friction model, common Kelvin-Voigt model etc. The nonlinear behavior of dynamic stiffness and damping of the mounts are investigated. Thirdly, simulations of engine vibration dynamics are presented and compared with these models and the difference between common Kelvin-Voigt model and other constitutive models are observed and analyzed.
2017-03-28
Technical Paper
2017-01-1023
Yaqun Jiang, C. Hsieh, Georg Festag, Masood Ahmed, William Jiang
Large axial displacement at the edge of a flywheel caused a clutch fail to disengage in high-speed rotation. To find out the root cause and solve the problem, a numerical procedure is proposed to investigate the vibration source and to understand dynamic behavior of the crank-train system. A simulation of the whole engine system including block, crankshaft, piston and connecting rod was performed with AVL/Excite. The baseline model was correlated with measurement. A comprehensive study was conducted for a set of flywheel and crankshaft models with different materials and unbalance masses. The contribution to flywheel wobbling of each vibration order was carefully investigated, and an optimal design was presented.
2017-03-28
Technical Paper
2017-01-1317
Luis Felipe Blas Martinez, Rodolfo Palma, Francisco Gomez, Dhaval Vaishnav, Francisco Canales
Liquid sloshing is an important issue in transportation, aerospace and automotive. Effects of sloshing in a moving liquid container can cause issues in: vehicle stability, safety, component fatigue, audible noise and comfort issues, fill level indication, etc. The sloshing phenomenon is a highly non-linear oscillatory movement of the free-surface of liquid inside a container (tank) under the effect of continuous or momentarily excitation forces. These excitation forces can result from sudden acceleration, braking, sharp turning or pitching motions. Due to the fluid inertia, waves are generated inside the tank, which can generate high pressure gradients over the tank surface when the fluid impacts the surface, causing the tank to vibrate resulting in fatigue loads. Structural fatigue in land vehicles is a major concern for loads in the 2-200 Hz range, but especially at the lower frequencies.
2017-03-28
Technical Paper
2017-01-1231
Chun Tang, Natee Limsuwan, Nurani Chandrasekhar, Zhichun Ma, Jacob Krizan, Joel Hetrick, Wei Wu
Abstract: Machine three phase current driven by PWM switching inverter in PM machine drive is not ideal sinusoidal, containing different levels of harmonics. The current harmonics have important impact on the electrical machine torque ripple which could translate into transmission and vehicle level noise vibration and harshness (NVH). In this work, the current waveforms were measured from dyno test at prescribed torque and speed levels, and the electric machine torque ripple was computed with the measured current. This paper will focus on the investigation of the current harmonics behaviors and features at various torque and speed conditions, the impact on torque ripple, and the possible mitigation method to reduce torque ripple.
2017-03-28
Technical Paper
2017-01-1229
Ken Yamamoto, Nobuyasu Sadakata, Hidetoshi Okada, Yusuke Fujita
Electric oil pumps (EOP) for automobiles are used to lubricate and cool moving mechanisms and supply oil pressure to components. Conventional EOPs consist of two separate units including a driver and a pump system comprised of a motor and a pump, which, as a result, impedes layout flexibility for vehicles. To overcome this shortcoming, we have developed an ECU-integrated oil pump in which a driver, a motor and a pump are incorporated as a single unit. In the course of the project, we focused on improving vibration resistance and developing a compact design. The first challenge was to improve vibration resistance because of the driver located in close proximity of the powertrain. Since the driver is installed on the motor unit via bus bars that are electrically welded, the joints of the driver and the bus bar become susceptible to vibration.
2017-03-28
Technical Paper
2017-01-0566
Ramachandra Diwakar, Vicent Domenech-Llopis
Historically stating, combustion noise from the passenger car diesel engines has been a major drawback for customer acceptance. The present modern automotive diesel engines operate quietly due to advancements in diesel injector technology and noise abatement strategies applied to the engine compartment of the vehicle itself. In the literature, recent experimental and analytical research work with a single cylinder direct-injection diesel engine has shown that the injection dwell time between the main injection pulse and the one preceding to it, is primarily responsible for the noise reduction The objective of the current analytical research work is to bring out the fundamental physics behind the experimentally observed noise reduction phenomena. The computational study was conducted at a key part-load operation of a direct-injection diesel engine (engine speed of 2000RPM and 5Bar BMEP) with five injection pulses.
2017-03-28
Technical Paper
2017-01-1057
Paul Zeng, Debabrata Paul, Vincent Solferino, Mark Stickler
Valvetrain ticking noise is one of the key failure modes in noise vibration harshness (NVH) evaluation at idle. It affects customer satisfaction inversely. In this paper, the root cause of the valvetrain ticking noise and key parameters that impact ticking noise will be presented. A physics based math model has been developed and integrated into a parameterized multi-body dynamic model. The analytical prediction has been correlated with testing data. Valvetrain ticking noise control is discussed.
2017-03-28
Journal Article
2017-01-1054
Imad M. Khan, Makrand Datar, Wulong Sun, Georg Festag, T Bin Juang, Natalie Remisoski
At various milestones during a vehicle’s development program, different CAE models are created to assess NVH error states of concern. Moreover, these CAE models may be developed in different commercial CAE software packages, each one with its own unique advantages and strengths. Fortunately, due to the wide spread acceptance that the Functional Mock-up Interface (FMI) standard gained in the CAE community over the past few years, many commercial CAE software now support cosimulation in one form or the other. Cosimulation allows performing multi-domain/multi-resolution simulations of the vehicle, thereby combining the advantages of various modeling techniques and software. In this paper, we explore cosimulation of full 3D vehicle model developed in MSC Adams® with 1D driveline model developed in LMS AMESim®. The target application of this work is investigation of vehicle NVH error states associated with series-parallel hybridized powertrains.
2017-03-28
Technical Paper
2017-01-1055
Baolin Yu, Zhi Fu, T. Bin Juang
The automotive industry is experiencing a profound change due to increasing pressure from environmental and energy concerns. This leads many auto makers to accelerate hybrid and electric vehicle development. Generally smaller engines utilized by hybrid and electric vehicles lend themselves to quieter operation. However, customer satisfaction could be negatively impacted by the peak whine emitted by electric motor. Unlike conventional gas vehicles, the strategy for reducing motor whine is still largely unexplored. This paper presents an analytical study on electric motor whine radiated from a hybrid vehicle transmission. The analysis includes two stages. Firstly a detailed finite element (FE) model of transmission is constructed, and case surface velocities are calculated utilizing electromagnetic force. Then a boundary element model is built for evaluating noise radiated from the transmission surface using acoustic transfer vector (ATV) method.
2017-03-28
Technical Paper
2017-01-1056
Rong Guo, Xiao-Kang Wei, Jun Gao
Commercial demands of comfort and stringent fuel economy have encouraged manufacturers to accommodate advanced technologies such as the Variable Displacement Engine (VDE), downsizing and so on in the new automotive models. Particularly, Active control engine mounts (ACMs) notably contribute to ensuring superior effectiveness in vibration suppression. This paper incorporates a PID controller into the active control engine mount system for inhabiting the transmitted force to the body. Furthermore, integrated time absolute error (ITAE) of the transmitted force is introduced to serve as the control goal for searching better PID parameters. Then the particle swarm optimization (PSO) algorithm is adopted for the first time to optimize the PID parameters in the ACM system. In the end, simulation results are presented for searching optimal PID parameters and validating the performance of the optimized PID control method.
2017-03-28
Technical Paper
2017-01-1059
Rong Guo, Jun Gao, Xiao-kang Wei
The active engine mount (AEM) is developed in automotive industry to improve overall NVH performance. The AEM is designed to reduce major order of engine vibration over a broad frequency range, therefore it is of vital importance to extract major order signals from vibration before the actuator of the AEM works. This paper focuses on a method of real-time extraction of the major order acceleration signals at the passive side of the AEM. Firstly, the transient engine speed is tracked and calculated, from which the FFT method with a constant sampling rate is used to identify the time-related frequencies as the frequency base. Then the major order signals in frequency domain are computed according to the certain multiple relation of the frequency base. After that, the major order signals of acceleration can be reconstructed in time-domain, which are proved accurate through offline simulation, compared with the given signal.
2017-03-28
Technical Paper
2017-01-0480
Mingde Ding
For structural application, composite parts structure is much more affected by load cases than steel part structure. Engine room bracket of EV, which is structural part and is used to bear Motor Controller, Charger and so on, has different load cases for different EV. Three commonest load cases that are Case 1: bearing 65kg (without suspension part), Case 2: bearing 68kg(including 3.5kg suspension part) and Case 3: bearing 70.1kg (including 5.6kg suspension part). According to topology optimization, structurel 1 was obtained, and then CAE analysis including (strength, stiffness and model) was carried out for abovement three load cases. For Case 1 and Case 2, the analysis result can meet the requirement. However, for Case 3, the stiffness and model analysis result can not satisfy the requirement. To meet the analysis result of Case 3, Structure 1 was optimized and structure 2 was obtained. The CAE analysis was conducted and the results can satisfy the requirements.
2017-03-28
Technical Paper
2017-01-1051
Hassan Nehme, Abdelkrim Zouani
Turbocharged engines constitute one of the strategies used by Ford Motor Company to deliver engines with improved fuel economy and performance. However, turbochargers exhibit many inherent NVH challenges that need to be addressed in order to deliver refined engines that meet customers’ expectations. One of these challenges is the turbocharger 1st order synchronous noise due to the interaction between the manufacturing tolerances of the rotating components and the dynamics of the rotor. This paper presents an analytical method to compute the turbocharger bearing forces and predict the 1st order synchronous noise and vibrations. The method consists of a fully coupled turbocharger rotor dynamic analysis in a flexible turbocharger housing structure; it predicts housing vibrations under various manufacturing tolerance conditions. The predicted vibrations of the turbocharger housing are compared to measured test data to demonstrate the validity of the analytical method.
2017-03-28
Technical Paper
2017-01-0439
Joydeep Chatterjee, Yuva Kishore Vaddi, Chetan Prakash Jain
Abstract In urban driving conditions, the steering vibration plays a major role for a customer, spending a significant amount of time behind the steering wheel. Considering the urban drive at Indian roads, 1000~1600rpm band becomes primary area of concern. In this paper, study has been conducted to define the target areas as well as its achievement in reference to given driving pattern on a front wheel powered passenger car for steering vibration. During the concept stage of vehicle development, a target characteristic of steering wheel vibration was defined based on the competitor model benchmarking and prior development experience. A correlated CAE model was prepared to evaluate the modification prior to prototype building and verification. Vibration level in all 3 degrees of freedom at the steering wheel location was measured in the initial vehicle prototypes and target areas of improvement are identified.
2017-03-28
Technical Paper
2017-01-0440
Jun Lu, Zhenfei Zhan, Haozhan Song, Xu Liu, Xin Yang, Junqi Yang
Abstract Noise-vibration-harshness (NVH) design optimization problems have become major concerns in the vehicle product development process. The Body-in-White (BIW) plays an important role in determining the dynamic characteristics of vehicle system during the concept design phase. Finite Element (FE) models are commonly used for vehicle design. However, even though the speed of computers has been increased a lot, the simulation of FE models is still too time-consuming due to the increase in model complexity. For complex systems, like vehicle body structures, the numerous design variables and constraints make the FE simulations based optimization design inefficient. This calls for the development of a systematic and efficient approach that can effectively perform optimization to further improve the NVH performance, while satisfying the stringent design constraints.
2017-03-28
Technical Paper
2017-01-0442
Harchetan Singh Aneja, Manas Tripathi, Harmeet Singh, Aashish Parmar
Abstract With the increasing expectation of customer for a quiet and comfortable ride, automobile manufacturers need to continuously work upon to improve automobile powertrain NVH. Today’s customer has become so aware of vehicle related noises that in-tank fuel pump noise is no exception to the checklist of evaluating cabin NVH. In-tank fuel pump, that is responsible for delivering the fuel from fuel storage tank to delivery rail, uses an electric driven motor. The rotating parts such as rotor, etc. produce vibrations that may traverse to tank body & subsequently vehicle body. Since noise is essentially an audible vibration at its root, these structure borne vibrations may be perceived as noise inside passenger cabin. Additionally, the noise may also be produced by fuel flow pulsations if transferred through piping to vehicle body. This paper focuses on various approaches to reduce the fuel pump generated noise heard inside passenger cabin.
2017-03-28
Journal Article
2017-01-0441
Zhenyu Wang, Mei Zhuang
Abstract A numerical study on sunroof noise reduction is carried out. One of the strategies to suppress the noise is to break down the strong vortices impinging upon the trailing edge of the sunroof into smaller eddies. In the current study, a serrated sunroof trailing edge with sinusoidal profiles of wavelengths is investigated for the buffeting noise reduction. A number of combinations of wavelengths and amplitudes of sinusoidal profiles is employed to examine the effects of trailing edge serrations on the noise reduction. A generic vehicle model is used in the study and a straight trailing edge is considered as a baseline. The results indicate that the trailing edge serration has a significant impact on the sound pressure level (SPL) in the vehicle cabin and it can reduce the SPL by up to 10~15 dB for the buffeting frequency.
2017-03-28
Journal Article
2017-01-1507
Prashanta Gautam, Yousof Azizi, Abhilash Chandy
The tire noise is caused due to the complex interactions between the rotating tire and the road surface at the tire/road interface. It is usually caused due to a combination of individually complex noise generation mechanisms, which can be either structural or air related. The influence of each of these noise generation mechanisms may vary, depending on various conditions such as tire design, road surface and operating conditions. Due to the many variables that affect the many noise generation mechanisms in tires, it is usually a very complex task to isolate and categorize those that are present in the overall tire/road noise spectrum. Various approaches are used to categorize noise generation mechanisms in tires. In this paper, a statistical model is used, under the assumption that the tire noise acoustic pressure at a specific frequency band is related to the vehicle speed, in order to study tire noise at different speeds.
2017-03-28
Technical Paper
2017-01-0445
Muthukumar Arunachalam, Arunkumar S, PraveenKumar Sampath, Abdul Haiyum, Yash Khakhar
In recent years, there is increasing demand for every CAE engineer on their confidence level of the virtual simulation results due to the upfront robust design requirement during early stage of an automotive product development. Apart from vehicle feel factor NVH characteristics, there are certain vibration target requirements at system or component level which need to be addressed during design stage itself in order to achieve the desired functioning during vehicle operating conditions. Vehicle passive safety system is one of which primarily consists of acceleration sensors, control module and air-bag deployment system. As the sensors act as the front-end of passive safety system and control module’s decision is based on these sensors signals, its mounting locations should meet the sufficient inertance or dynamic stiffness performance in order to avoid distortion in signals due to its structural resonances.
2017-03-28
Technical Paper
2017-01-0446
Xiao Chuan Xu, Xiuyong Shi, Jimin Ni, Jiaqi Li, Xiaochuan Xu Sr.
Abstract Oil pump is a critical part of engine lubrication system. The performance and efficiency of oil pump are greatly affected by vibration and noise, which would lead to the pump service life decreasing and pump body easily wearing. Hence the vibration and noise of oil pump is of great importance to study. In this paper, a FEA model of the variable displacement oil pump(VDOP) was established to carry on the modal and noise analysis, while the geometric structure was optimized with test verification. The modal analysis of VDOP was carried out by ABAQUS software, the 3-D unsteady flow field in VDOP was simulated by Pumplinx software, and the sound field was analyzed by ACTRAN acoustic module. Using a special oil pump test bench combined with B&K PULSE vibration and noise test equipment, the NVH and comprehensive performance experiment of the VDOP were carried out here.
2017-03-28
Technical Paper
2017-01-0448
Prakash T. Thawani, Stephen Sinadinos, John Zvonek
Abstract With the advent of EVs/HEVs and implementation of Idle-Stop-Start (ISS) technologies on internal combustion engine (ICE) driven cars/trucks to improve fuel economy and reduce pollution, refrigerant sub-system (RSS) induced noise phenomena like, hissing, gurgling and tones become readily audible and can result in customer complaints and concerns. One of the key components that induce these noise phenomena is the Thermostatic Expansion Valve (TXV). The TXV throttles compressed liquid refrigerant through the evaporator that results in air-conditioning (A/C) or thermal system comfort for occupants and dehumidification for safety, when needed. Under certain operating conditions, the flow of gas and/or liquid/gas refrigerant at high pressure and velocity excites audible acoustical and structural modes inherent in the tubing/evaporator/HVAC case. These modes may often get masked and sometimes enhanced by the engine harmonics and blower noise.
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