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Viewing 181 to 210 of 7819
2017-03-28
Technical Paper
2017-01-1553
Min Kyoo Kang, Jin Hong Kim, HyuckJin Oh, Wookjin Jang, Sangwoo Lee, Young Hwan Lee
Abstract This paper presents a transient vibration analysis of a nonlinear full-vehicle. The full-vehicle model consists of a powertrain, a trimmed body, a drive line, and front and rear suspensions with tires. It is driven by combustion forces and runs on a road surface. By performing time-domain simulation, it is possible to capture nonlinear behavior of a vehicle such as preload due to gravitational force, large deformation, and material nonlinearity which cannot be properly treated in the conventional steady state analysis. In constructing a full-vehicle, validation process is essential. Validation process is applied with respect to the assembling sequence. The validation starts with component levels such as tires, springs, shock absorbers, and a powertrain, and then the full-vehicle model is constructed. Model validation is done in two aspects; one is model accuracy and the other is model efficiency.
2017-03-28
Technical Paper
2017-01-0566
Ramachandra Diwakar, Vicent Domenech-Llopis
Abstract With the ability of modern high pressure diesel injectors to deliver accurate, closely coupled multiple pulse injections, it is possible to minimize engine combustion noise without negative effect on exhaust emissions. Literature shows that, splitting the cycle heat release into several parts helps to lower peak heat release rate and combustion noise. The charge cooling caused by fuel vaporization can be effectively used to influence ignition delay and achieve lower noise, emissions and fuel consumption. With the traditional pilot-main injection scheme, researchers have shown that, the injection dwell time between the pilot and main is primarily responsible for noise reduction. The current objective is to analytically explore the fundamental physics behind the experimentally observed noise reduction phenomena with multiple injections. This computational study was conducted at a key part-load operation (2000RPM and 5Bar BMEP) with five injection pulses.
2017-03-28
Technical Paper
2017-01-0172
Suhas Venkatappa, Manfred Koberstein, Zhengyu Liu
Abstract The refrigerant transition from HFC-134a to HFO-1234yf has proven to be more challenging on controlling refrigerant flow-induced noises generated from automotive air-conditioning (A/C) systems than originally anticipated. The objectives of this paper are to describe the noise issues with HFO-1234yf, understand the mechanisms and key factors affecting HFO-1234yf refrigerant flow-induced noise. Finally, the countermeasures and guidelines for attenuating and suppressing the noise are presented.
2017-03-28
Technical Paper
2017-01-0447
Zhe Li, Mike Dong, Dennis Harrigan, Michael Gardner
In gasoline Powertrain systems, the evaporative emission control (EVAP) system canister purge valve (CPV) can be actuated by pulse-width modulated (PWM) signals. The CPV is an electronically actuated solenoid. The PWM controlled CPV, when actuated, creates pressure pulsations in the system. This pulsation is sent back to the rest of the EVAP system. Given the right conditions, the fill limit vent valve (FLVV) inside the fuel tank can be excited. The FLVV internal components can be excited and produce noise. This noise can be objectionable to the occupants. Additional components within the EVAP system may also be excited in a similar way. This paper presents a bench test method using parts from vehicle’s EVAP system and other key fuel system components.
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
2017-01-0445
Muthukumar Arunachalam, Arunkumar S, PraveenKumar Sampath, Abdul Haiyum, Yash Khakhar
Abstract 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 which primarily consists of acceleration sensors, control module and air-bag deployment system. Control module’s decision is based on accelerometer sensor signals so that 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
2017-01-0443
Yong Hyun Nam, Gwansik Yoon
Abstract Significant effort has been expended to improve the sound made by a closing car door. This study focuses on reducing door glass rattle sounds, not only evaluating the rattle influence of door glass support but also introducing an approach to reduce glass rattle noise by using sealing components. The first part of the study is dedicated to minimizing vibration. A jig is constructed to evaluate the influence of a door glass support on the rattling. The jig is employed so that the glass meshing between the A and B pillars can be controlled; the glass holder moves in the x- and z-directions and the belt molding moves in the y-direction. An impact hammer test was adopted for investigating door glass rattle. The frequency response obtained via impact hammer testing is analyzed by varying the glass support points and important factors that should be considered in early design stages are obtained. The second study is about optimizing vibration absorption.
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
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
2017-01-0439
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
2017-01-0448
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.
2017-03-28
Technical Paper
2017-01-0405
Tianqi Lv, Xingxing Feng, Peijun Xu, Yunqing Zhang
Abstract Three 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, Three constitutive models for filled elastomers are implemented for the engine mounts of the PMS, including: (1) Model 1: Kelvin-Voigt model; (2) Model 2: Fractional derivative Kelvin-Voigt model combined with Berg’s friction; (3) Model 3: Generalized elastic viscoelastic elastoplastic model. The nonlinear behaviors 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 differences between common Kelvin-Voigt model and other constitutive models are observed and analyzed.
2017-03-28
Technical Paper
2017-01-0376
Jianyong Liang, Jonathan Powers, Scott Stevens, Behrooz Shahidi
Abstract While Advanced High Strength Steels (AHSS) and the next generation AHSS 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 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
2017-01-1052
Paul Zeng, Vincent Solferino, Mark Stickler
Abstract 1 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
2017-01-1051
Hassan Nehme, Abdelkrim Zouani
Abstract EcoBoost 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 customer’s expectation. 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 dynamic behavior of the rotor. This paper discusses an MBD/FEA/BEM based method to predict the nonlinear dynamic behavior of the rotor semi floating bearing, its impact on the bearing loads and the resulting powerplant noise due to the interaction with the turbocharger imbalance level.
2017-03-28
Technical Paper
2017-01-1056
Rong Guo, Xiao-Kang Wei, Jun Gao
Abstract Manufacturers have been encouraged to accommodate advanced downsizing technologies such as the Variable Displacement Engine (VDE) to satisfy commercial demands of comfort and stringent fuel economy. Particularly, Active control engine mounts (ACMs) notably contribute to ensuring superior effectiveness in vibration attenuation. This paper incorporates a PID controller into the active control engine mount system to attenuate 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. Simulation results are presented for searching optimal PID parameters. In the end, experimental validation is conducted to verify the optimized PID controller.
2017-03-28
Technical Paper
2017-01-1055
Baolin Yu, Zhi Fu, T. Bin Juang
Abstract The automotive industry is experiencing a profound change due to increasing pressure from environmental and energy concerns. This leads many automakers to accelerate hybrid and electric vehicle development. Generally hybrid and electric vehicles create less noise due to their compact engines (or no engine). 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 the transmission in a hybrid vehicle. The analysis includes two stages. Firstly, a detailed finite element (FE) model of the transmission is constructed, and case surface velocities are calculated utilizing motor 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
2017-01-1058
L.V. Pavan Kumar Maddula, Ibrahim Awara
Abstract Increased focus on fuel efficiency and vehicle emissions has led the automotive industry to look into low weight alternative designs for powertrain system components. These new design changes pose challenges to vehicle attributes like NVH, durability, etc. Further, the requirement of high power applications produces even more complexities. The present work explains how a potential design change of half shafts driven by a desire to reduce weight and cost can lead to NVH problems caused by half shaft resonances and explains how using multiple dynamic vibration absorbers can solve the issue to meet customer expectation while improving efficiency. With the aid of Finite Element Analysis (FEA) & optimization software, interactions between multiple DVA’s on a system was understood and optimal damper parameters for effective damping was identified. The final DVA design was tested and verified on the vehicle for optimal attribute performance.
2017-03-28
Technical Paper
2017-01-1057
Paul Zeng, Debabrata Paul, Vincent Solferino, Mark Stickler
1. Abstract 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
Technical Paper
2017-01-1059
Rong Guo, Jun Gao, Xiao-kang Wei
Abstract The active engine mount (AEM) is developed in automotive industry to improve overall NVH performance. The AEM is designed to reduce major-order signals 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 work 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 fundamental frequencies. Then the major-order signals in frequency domain are computed according to the certain multiple relation of the fundamental frequencies. After that, the major-order signals can be reconstructed in time domain, which are proved accurate through offline simulation, compared with the given signals.
2017-03-28
Technical Paper
2017-01-1062
Abdelkrim Zouani, Gabriela Dziubinschi, Vidya Marri, Simon Antonov
Abstract In modern automotive engines, Variable Displacement Oil Pump (VDOP) is becoming the pump of choice to enable reduction in friction and delivery of stringent fuel economy. However, this pump creates pressure ripples, at the outlet port during oil pump shaft rotation, causing oscillating forces within the system and leading to the generation of tonal noises and vibrations. In order to minimize the level of noise, different porting geometries and vane spacing are used. This paper describes an optimization method intended to identify the best possible spacing of the vanes in the conventional 7-vanes, 9-vanes and 11-vanes oil pumps. The method integrates a Matlab routine with the modeFRONTIER software to create the required design space in order to perform a multi-objective optimization using a genetic algorithm. Results of this optimization method are discussed and a design guideline for the VDOP vane spacing is disclosed.
2017-03-28
Technical Paper
2017-01-1061
Jiachen Zhai, Ma Conggan
Abstract Electric vehicle driving permanent magnet synchronous motor has a wide speed range and load changes, with abundant harmonic currents, and its eccentric form is complex, which all result in poor sound quality and abnormal noise problems becoming increasingly prominent. To make a systematic and thorough study of the centralized drive permanent magnet synchronous motor (PMSM) is significant to ameliorate the sound quality and solve noise problems. MATLAB-based modeling technology, SPSS software, and the establishment of sound quality evaluation model for the centralized drive PMSM has a crucial reference value on the research and development of the electric vehicle driving permanent magnet synchronous motor. As for the sound quality of centralized drive PMSM, firstly, in order to get objective parameter values, evaluation models of objective parameters based on psychological acoustics should be established after the collection of the sound samples.
2017-03-28
Technical Paper
2017-01-0455
Harshad Hatekar, Baskar Anthonysamy, V. Saishanker, Lakshmi Pavuluri, Gurdeep Singh Pahwa
Abstract Structural elastomer components like bushes, engine mounts are required to meet stringent and contrasting requirements of being soft for better NVH and also be durable at different loading conditions and different road conditions. Silent block bushes are such components where the loading in radial direction of bushes are high to ensure the durability of bushes at high loads, but has to be soft on torsion to ensure good NVH. These requirements present with unique challenge to optimize the leaf spring bush design, stiffness and material characteristics of the rubber. Traditionally, bushes with varying degree of stiffness are selected, manufactured and tested on vehicle and the best one is chosen depending on the requirements. However, this approach is costly, time consuming and iterative. In this study, the stiffness targets required for the bush were analysed using static and dynamic load cases using virtual simulation (MSC.ADAMS).
2017-03-28
Technical Paper
2017-01-0449
Yinzhi He, Bin Wang, Zhe Shen, Zhigang Yang, Gunnar Heilmann, Tao Zhang, Guoxu Dong
Abstract Beamforming techniques are widely used today in aeroacoustic wind tunnels to identify wind noise sources generated by interaction between incoming flow and the test object. In this study, a planar spiral microphone array with 120 channels was set out-of-flow at 1:1 aeroacoustic wind tunnel of Shanghai Automotive Wind Tunnel Center (SAWTC) to test exterior wind noise sources of a production car. Simultaneously, 2 reference microphones were set in vehicle interior to record potential sound source signal near the left side view mirror triangle and the signal of driver’s ear position synchronously. In addition, a spherical array with 48 channels was set inside the vehicle to identify interior noise sources synchronously as well. With different correlation methods and an advanced algorithm CLEAN-SC, the ranking of contributions of vehicle exterior wind noise sources to interested interior noise locations was accomplished.
2017-03-28
Technical Paper
2017-01-0875
Valentin Soloiu, Jose Moncada, Martin Muinos, Aliyah Knowles, Remi Gaubert, Thomas Beyerl, Gustavo Molina
Abstract This paper investigates the performance of an indirect injection (IDI) diesel engine fueled with Bu25, 75% ultra-low sulfur diesel (ULSD#2) blended with 25% n-butanol by mass. N-butanol, derivable from biomass feedstock, was used given its availability as an alternative fuel that can supplement the existing limited fossil fuel supply. Combustion and emissions were investigated at 2000 rpm across loads of 4.3-7.2 bar indicated mean effective pressure (IMEP). Cylinder pressure was collected using Kistler piezoelectric transducers in the precombustion (PC) and main combustion (MC) chambers. Ignition delays ranged from 0.74 - 1.02 ms for both operated fuels. Even though n-butanol has a lower cetane number, the high swirl in the separate combustion chamber would help advance its premixed combustion. The heat release rate of Bu25 became initially 3 J/crank-angle-degree (CAD) higher than that of ULSD#2 as load increased to 7.2 bar IMEP.
2017-03-28
Technical Paper
2017-01-1311
Suman Mishra, Nagesh Gummadi, Lloyd Bozzi, Neil Vaughn, Rob Higley
Abstract Air rush noise is exhaust gas driven flow-induced noise in the frequency range of 500-6500 Hz. It is essential to understand the flow physics of exhaust gases within 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 air rush noise of exhaust mufflers in the aforementioned frequency range at a typical exhaust flow rate and temperature. The study is performed on two 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
2017-01-1317
Luis Felipe Blas Martinez, Rodolfo Palma, Francisco Gomez, Dhaval Vaishnav, Francisco Canales
Abstract Liquid sloshing is an important issue in ground transportation, aerospace and automotive applications. Effects of sloshing in a moving liquid container can cause various issues related to vehicle stability, safety, component fatigue, audible noise and, liquid level measurement. The sloshing phenomenon is a highly nonlinear oscillatory movement of the free-surface of liquid inside a container under the effect of continuous or momentarily excitation forces. These excitation forces can result from sudden acceleration, braking, sharp turning or pitching motions. The sloshing waves generated by the excitation forces can impact on the tank surface and cause additional vibrations. For the loads with the frequencies between 2 to 200 Hz, the structural fatigue failure is a major concern for automotive applications.
2017-03-28
Technical Paper
2017-01-1121
Deb Bonnerjee, Djamel Bouzit, Javed Iqbal
Abstract Automobile customers are looking for higher performance and quieter comfortable rides. The driveline of a vehicle can be a substantial source of NVH issues. This paper provides an understanding of a driveline noise issue which can affect any variant of driveline architecture (FWD, AWD, RWD and 4X4). This metallic noise is mostly present during the take-off and appropriately termed as ting noise. This noise was not prevalent in the past. For higher fuel economy, OEMs started integrating several components for lighter subsystems. This in effect made the system more sensitive to the excitation. At present the issue is addressed by adding a ting washer in the interface of the wheel hub bearings and the halfshafts. This paper explains the physics behind the excitation and defines the parameters that influence the excitation. The halfshaft and the wheel hub are assembled with a specified hub nut torque.
2017-03-28
Technical Paper
2017-01-1122
Yashodhan V. Joshi
Abstract Vehicle noise has reduced over the years due to the customer demand for quieter vehicles. As the background noises such as combustion noise, pumping noise, etc. have reduced, mechanical noises such as gear noise have become prominent and a major cause of customer complaints. Engine timing gear train uses gears for transferring torque to cam and accessory gears. As engines have become quieter by efforts to reduce the combustion noise, as well as, by moving away from mechanical fuel pumps to common rail fuel pumps, the gear train noise has come under increased scrutiny. Gear whine could be a result of multiple factors. Gear profile distortion is one of the factors. Gear torque variation also has a significant effect on gear whine. Operation of the accessory drives such as hydraulic pumps under variable loads and speeds, is one of the major challenges for resolving a gear whine issue in the engine gear train.
2017-03-28
Technical Paper
2017-01-1125
Victor Baumhardt, Valdinei Sczibor
Abstract Halfshafts are very important components from vehicle powertrain. They are the element responsible to transmit torque and rotation from transmission to wheels. Its most basic design consists of a solid bar with joints at each extreme. Depending of bar length, the natural frequency of first bending mode might have a modal alignment with engine second order, resulting in undesired noise on vehicle interior. Many design alternatives are available to overpass this particular situation, like adding dampers, use tube shafts or use link-shafts, however, all of them are cost affected. This study proposes an investigation to obtain an optimal profile for a solid shaft, pursuing the lowest possible frequency for the first bending mode by changing its diameter at specific regions. The study is divided in four main stages: initially, a modal analysis of a halfshaft is done at vehicle to determinate its natural frequency when assembled on vehicle.
Viewing 181 to 210 of 7819

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