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Article
2014-04-07
Multiquip recently chose Exa to evaluate and reduce noise propagation from its containerized power generators.
Article
2014-04-07
The Maulflex conduit system from TE Connectivity is a lightweight, flexible, customizable shielded electrical conduit system for rugged environments.
Article
2014-04-07
XCal-View software from Renishaw offers improved functionality and flexibility for laser calibration data analysis.
Article
2014-04-04
According to CD-adapco's Frederick Ross, the first, and most difficult, stage in the construction of a virtual prototype is the process of pulling together all of the individual CAD parts that define a vehicle.
Article
2014-04-01
Palmer Wahl Instrumentation Group’s Wahl DST500-FM temperature indicator with fixed probes is a high-accuracy, wide-range thermometer designed for hazardous locations where accurate and reliable temperature monitoring is critical.
Article
2014-04-01
Dakota Instruments’ 6A03 acrylic flow meters are offered with interchangeable direct reading scales for air, water, argon, oxygen, carbon dioxide, nitrogen, helium, and hydrogen.
Technical Paper
2014-04-01
Joe Serrano, Geoff Routledge, Norman Lo, Mark Shost, Vijay Srinivasan, Biswa Ghosh
Cylinder deactivation is a technology seeing increased automotive deployment in light of more demanding fuel economy and emissions requirements. Examples of current production systems include GM's Active Fuel Management and Chrysler's Multi-Displacement System, both of which provide one fixed level of deactivation. Dynamic Skip Fire (DSF), in which the number of fired cylinders is continuously varied to match the torque demand, offers significantly increased fuel savings over a wider operating range than the current production systems. One of the biggest challenges in implementing cylinder deactivation is developing strategies to provide acceptable Noise, Vibration and Harshness (NVH); this paper discusses those challenges and the methodologies developed. This work covers theoretical root causes; proposed metrics to quantify the NVH level; algorithmic and physical mitigation methods; and both subjective and objective evaluation results.
Technical Paper
2014-04-01
Kenji Torii
A technique was created to separate the contributions of combustion noise and mechanical noise to engine noise in the time domain in order to achieve efficient measures for enhancing the sound quality of combustion noise. There is an existing technique based on 1/3 octave band analysis that is known as a method for separating the contributions to engine radiation noise, but this technique cannot provide time-domain data. Therefore, the author has proposed a technique that separates engine radiation noise into combustion noise and mechanical noise in the time domain by finding the combustion noise for each cylinder and calculating its structural response function by considering its real and imaginary components. Results of analysis of actual engine radiation noise with this technique confirmed that combustion noise, which is characterized by strong pulsation, and irregular mechanical noise can be separated in the time domain with good precision. Moreover, the structural response function, combustion noise, and mechanical noise characteristics showed a valid changing trend in response to changes in cylinder pressure and structural specifications.
Technical Paper
2014-04-01
S. Christopher Zugo, Craig D. Smith, Charles W. Braun, Joseph Kazour
Abstract The audible noise characteristics of direct injectors are important to OEM customers when selecting a high pressure gasoline fuel injector. The activation noise is an undesirable aspect that needs to be minimized through injector design, injector mounting, and acoustic treatments. Experimentally identifying the location and frequency of noise sources is beneficial to the improvement of injector designs. Acoustic holography is a useful tool in locating these noise sources by measuring a sound pressure field with multiple microphones and using this field to estimate the source location. For injector testing, the local boundary conditions of the noise source will affect the resultant sound field. Therefore, how the injector is mounted within the test fixture will change the resultant noise field measured. In this study, the process of qualifying an acoustic holography fixture using measurement system analysis for GDi fuel injector testing will be documented. The noise levels and source locations for different injector mounting conditions will be evaluated.
Technical Paper
2014-04-01
Sandeep Mahadev Jadhav
Abstract Objective of this research is to reduce gear rattle and whine noise. Study includes measurement of noise, vibration on transmission for source identification in order to eliminate rattle, whine through optimization of gear design and clutch damper performance. In order to optimize, we measured transmission torsional vibration and analyzed for proper selection of clutch dampers to reduce engine vibration transfer function to transmission. Through Noise & Vibration FFT, order and color map analysis we identified noise sources and further scope for specific gears design improvement. Hence test methodology adopted for development of gears and clutch damper successfully eliminated noise.
Technical Paper
2014-04-01
Manivasagam Shanmugam, Raghavendra Kharatmal, Shirish Satpute
Abstract This paper describes the rapid design and development of thin walled powertrain components which act as external cover for engine subsystem assemblies. Computer Aided Engineering plays a major role in reducing the overall product development lead time. An approach by using ‘Simulation Driven Design and Development’ helps the developers to bring the necessary confidence about the components' required functionality during the design stage itself. During the design stage, typical inputs available for the development of these components are the broad dimensions obtained from the packaging considerations. The designer is required to develop the concepts targeting least noise radiation from component surfaces due to various excitations. Based on cost considerations, the designer can even opt for plastic materials instead of steel. The current paper considers two major noise radiation members namely valve cover and timing gear cover for rapid product development. A conventional modal analysis followed by harmonic response studies provides the basis for the iterations towards designing these members.
Technical Paper
2014-04-01
George Nerubenko
Abstract The results of dynamical study of new patented Torsional Vibration Damper for an engine crankshaft are presented. Design and structure of Torsional Vibration Damper is based on author's US Patent 7,438,165 having the control system with instantaneous frequencies tuner for all frequencies in running engine. Basically the tuner should be designed in three optional manners: having mechanical structure, electromechanical structure with control system and micro-channels filled by electrolyte solution. The focus of the study is on Torsional Vibration Damper equipped with micro-channels filled by electrolyte solution. Mathematical model based on the system of ordinary differential equations describing the rotation and vibration of mechanical components combined to Navier-Stokes equations reflecting the fluid flow and Poisson - Boltzmann equations applicable for electrolyte solution flow in micro-channels has been used for the analysis of the dynamic behavior of engine crankshaft system having proposed Torsional Vibration Damper.
Technical Paper
2014-04-01
Mehdi Safaei, Shahram Azadi, Arash Keshavarz, Meghdad Zahedi
Abstract The main end of this research is the optimization of engine sub-frame parameters in a passenger car to reduce the transmitted vibration to vehicle cabin through DOE method. First, the full vehicle model of passenger car including all its sub-systems such as engine, suspension and steering system is modeled in ADAMS/CAR and its accuracy is validated by exerting swept sine and step input. After that, the schematic geometry of sub-frame is modeled in CAD software and transferred to ADAMS/CAR. Hence, the efficiency of the sub-frame in terms of reducing the induced vibration to vehicle cabin is examined through the various road inputs e.g. swept sine, step and random road input type (B). The results will illustrate that the sub-frame has significant effect in reduction of transmitted vibration to occupants. In order to optimize the sub-frame parameters, the sensitivity analysis is performed to derive effective parameters of sub-frame using DOE method. In this regard, the parameters which have dominant effect on transmitted vibration (the stiffness of sub-frame bushing in vertical direction) are optimized via RSM (Response Surface Method) method.
Technical Paper
2014-04-01
Sameer U. Kolte, David Neihguk, Abhinav Prasad, Samir Rawte, Aditya Gondhalekar
Abstract A typical powertrain mount design process starts with performing the system calculations to determine optimum mount parameters, viz. position, orientation and stiffness values to meet the desired NVH targets. Therefore, a 6 degrees of freedom lumped parameter system of powertrain and mounts is modelled in Matlab®. The approach is to decouple the torque roll axis mode from the remaining five rigid body modes so that the response to the torque pulses is predominantly ‘oscillations about Torque Roll Axis’. This is achieved by optimizing the above mount parameters within specified constraints so that ‘Rotation about the torque roll axis’ is one of the natural modes of vibration. The tool developed here uses ‘Particle Swarm Optimization(PSO) algorithm’ because of its ease of implementation and better convergence to the solution. The algorithm is programmed in TK solver®. Further, for the given torque input, the harmonic response of the powertrain mounted on optimized mounts, is evaluated for comparison with NVH targets.
Technical Paper
2014-04-01
Chien- Hsing Li, Yong-Yuan Ku, Ko Wei Lin
Abstract Due to the energy safety and environment protection, increase the percentage of biodiesel blend has become one of world wide strategies. In the past research, using biodiesel would affect the engine performance and increase the exhaust emission. Fortunately, these problems can be solved through the rapidly development of engine control technologies and lightweight structure design. However, the consideration of light/downsizing engine design with the same power has brought out much combustion noise. According to the higher and higher proportion has been widely used over the world. There was less researches focus on the different blending biodiesel impact on combustion noise. The combustion noise correspond to different blending biodiesel (D100,B5,B8,B20,B40,B100) which made form waste cooking oil has been discussion in this study. The experimental by using engine which meet EURO-4 was designed to caught spectrum of the combustion noise via transient window which under the constant engine speed of 1500rpm, 2000rpm, 2500rpm, with different torque at 30%, 50% and 70% of each speed, respectively.
Technical Paper
2014-04-01
Zhengfei Tang, Yongfu Chen, Jian Zeng, Yu Yang, Yunqing Zhang
NVH quality is one of the most important criteria by which people judge the design of a vehicle. The Powertrain Mounting System (PMS), which can reduce the vibration from engine to vehicle cab as well as the inside noise, has attained significant attention. Much research has been done on the isolation method for three- and four-point mounting. But the six-point mounting system, which is usually equipped in commercial vehicle, is seldom studied and should be paid more attention. In this paper, the support rod installed on the upside of the transmission case is considered as a flexible body. Thus a rigid-flexible coupling model of PMS is established and the necessity of the established model is analyzed by comparing the simulation results of the new model and those of the conventional model. Based on the traditional theory of energy decoupling and reasonable allocation of the natural frequencies, Adams and MATLAB are integrated into the optimization software iSIGHT to optimize the six-point PMS.
Technical Paper
2014-04-01
Hiroki Yamaura, Masao Ishihama, Kazuhide Togai
Engine torque profile shaping strategies have been proposed to reduce noise & vibration for passenger cars. However, it has not been sufficiently studied that feasible torque profile for vibration suppression is dependent on engine speed and target torque shape. On the other hand, combustion pressure profile shaping strategies have been proposed to reduce noise. However, there is almost no research of the quantitative evaluation of contribution of combustion pressure profile. First, the torque profile shaping was studied. Pre-compensated torque and 2-step torque were selected as typical target torque profiles. An effectiveness of vibration suppression by two torque profiles was evaluated by both drivetrain vibration model and engine torque profile model which have been established well. As a result of studying the torque profile shaping, timing of torque rise by the 2-step torque generation is delayed or advanced. Torque profile by the pre-compensation is deformed in steep change part.
Technical Paper
2014-04-01
Xiaobing Liu, Paul Nahra, Anna Strehlau
Abstract Engine stop/start systems are one technology being developed to meet ever tightening fuel economy regulations. Several production vehicles in the market have adopted stop/start systems with 12 volt batteries and enhanced starters. During engine autostart events (restart after autostop), the engine/vehicle vibration may be objectionable to customers. In this paper, the impact of extended range retarded intake cam phasing on first cycle combustion and vehicle vibration during engine autostart is provided. The engine intake cam phasers of a production vehicle were modified so the effective compression during autostart could be set as low as 3.5. Achieving these autostart conditions while maintaining typical cam timing positions under cold start conditions is achievable with an innovative dual park phaser. NVH measurements and engine speed traces indicate that this approach reduced vibration during engine autostart by a measurable amount. Subjective driver feedback was also positive.
Technical Paper
2014-04-01
Daniela Siano, Luigi Teodosio, Vincenzo De Bellis, Fabio Bozza
Abstract The present paper reports 1D and 3D CFD analyses of the air-filter box of a turbocharged VVA engine, aiming to predict and improve the gas-dynamic noise emissions through a partial re-design of the device. First of all, the gas-dynamic noise at the intake mouth is measured during a dedicated experimental campaign. The developed 1D and 3D models are then validated at full load operation, based on experimental data. In particular, 1D model provides a preliminary evaluation of the radiated noise and simultaneously gives reliable boundary conditions for the unsteady 3D CFD simulations. The latter indeed allow to better take into account the geometrical details of the air-filter and guarantee a more accurate gas-dynamic noise prediction. 3D CFD analyses put in evidence that sound emission mainly occur within a frequency range of 350 to 450 Hz. Starting from the above result, the original air-box design is modified through the installation of a single Helmholtz resonator, taking into account layout constraints and the influence on engine performance, as well.
Technical Paper
2014-04-01
Michael Delbaere, Didier Frachon, Gerald Masson
Abstract Many synchronous electric motors require a very accurate position sensor compatible with a sinusoidal control. The purpose of such a control is to enable an efficient and smooth operation enhancing the comfort by limiting vibrations. In some cases related to mechanical constraints, we have to deal with through-shaft design. One can quote for examples power drives for Electric or Hybrid Electric Vehicles as well as for Electric Power Steering motor. More generally, these sensors need to keep a simple and robust design and a restricted number of parts as they are submitted to high vibration levels, a wide temperature range and speeds of several krpm. In order to meet such requirements, MMT has developed a magnetic sensor principle offering a competitive alternative to the conventional inductive resolver type sensors. The basics of this solution is a through shaft angular position sensor using one or two Hall-effect probes. These Hall IC measure the angle of the magnetic field generated by a ring or a disc magnet.
Technical Paper
2014-04-01
Xiaoxun Chen, Yu Zhang, Yunqing Zhang, Ming Jiang
Abstract In the present study, the research of the exhaust system is performed in three steps. In the first step, the average driving degree of freedom displacement (ADDOFD) is calculated by the free modal analysis of the exhaust system. It is easy to find the reasonable location of the hanger according to the value of the ADDOFD, since it represents the relative size of some DOF's response displacement at excitation state. The second of which is to analyse the vibration isolation performance of the exhaust system based on the first step. The dynamic analysis of the exhaust system together with the powertrain is studied, by which way the unit sinusoidal excitation is applied at the powertrain's mass centre, so that the response force at the hanger can be obtained. Finally, the relationship between the constrained model of the exhaust system and the stiffness of the hanger is investigated, which is significant in engineering.
Technical Paper
2014-04-01
Marco Mammetti, Marina Roche Arroyos
Abstract Over recent years IDIADA has developed several prototype electric vehicles as well as testing a number of electric powertrain configurations. Generally the electric motor output shaft delivers the torque to the transmission under a considerable level of high-frequency load variation and with noticeable torque irregularities that must be smoothed out in order to fulfill general NVH targets. This paper deals with the development phase of a prototype vehicle in which a specific testing activity was carried out to improve the overall NVH behavior of the powertrain. For this purpose, the mechanism of energy transference from the current to the motor and from the motor to the downstream driveline components was deeply characterized. The activity was aimed at smoothing the abrupt change in torque delivery and limiting the transfer of torque irregularities from the motor to the transmission. The torque control software calibration and the driveline elements were developed in order to reduce the noise and vibration critical frequency ranges.
Technical Paper
2014-04-01
Miguel De la Cruz, Stephanos Theodossiades
Abstract In this paper, a direct correlation between transmission gear rattle experiments and numerical models is presented, particularly focusing on the noise levels (dB) measured from a single gear pair test rig. The rig is placed in a semi-anechoic chamber environment to aid the noise measurements and instrumented with laser vibrometers, accelerometers and free field microphones. The input torsional velocity is provided by an electric motor, which is controlled by a signal generator, aiming to introduce an alternating component onto the otherwise nominal speed; thus, emulating the engine orders found in an internal combustion engine. These harmonic irregularities are conceived to be the triggering factor for gear rattle to occur. Hence, the rig is capable of running under rattling and non-rattling conditions. The numerical model used accounts for the gear pair's torsional dynamics, lubricated impacts between meshing teeth and bearing friction. The results show that rattle is indeed triggered by the governing engine orders present in the transmission's primary input shaft.
Technical Paper
2014-04-01
Zamir Zulkefli, Maurice Adams
Abstract Gears are used in numerous applications where mechanical power needs to be transmitted as in the powertrain of cars, buses and other vehicles. These gears can potentially be a significant source of high-frequency vibration and radiated noise in a vehicle, which can be both harmful and objectionable to any listeners in the vicinity. A proposed approach to addressing the gear mesh-frequency vibrations is to utilize the low pass filtering effect of a hydrostatic bearing in a gear mesh-frequency noise mitigation system. This paper describes an experimental investigation of the low pass filtering effect of a hydrostatic bearing using an experimental setup involving a widely available materials testing machine. By using the materials testing machine, appropriately sized hydrostatic bearing and externally pressurized fluid supply system, empirical data was collected that allowed the frequency response of the hydrostatic bearing to be determined. The frequency response of the hydrostatic bearing clearly shows a low pass filtering effect on the applied dynamic loads.
Technical Paper
2014-04-01
Gaurav Gupta, Rituraj Gautam, Chetan Prakash Jain
Abstract Interior sound quality is one of the significant factors contributing to the comfort level of the occupants of a passenger car. One of the major reasons for the deterioration of interior sound quality is the booming noise. Booming noise is a low frequency (20Hz∼300Hz) structure borne noise which occurs mainly due to the powertrain excitations or road excitations. Several methods have been developed over time to identify and troubleshoot the causes of booming noise [1]. In this paper an attempt has been made to understand the booming noise by analyzing structural (panels) and acoustic (cavity) modes. Both the structural modes and the acoustic modes of the vehicle cabin were measured experimentally on a B-segment hatchback vehicle using a novel approach and the coupled modes were identified. Panels contributing to booming noise were identified and countermeasures were taken to modify these panels to achieve decoupling of structural and cavity modes which results in the reduction of cabin noise levels.
Technical Paper
2014-04-01
Manchi Venkateswara Rao, Jos Frank, Prasath Raghavendran
Abstract The customer demand for all wheel drive (AWD) vehicles is increasing over the period of time which also requires NVH performance on par with front wheel drive vehicles. AWD vehicles are equipped with power transfer unit, propeller shaft and independent rear differential assembly to achieve their functional requirement. The additional drive train components in AWD vehicles may amplify torsional fluctuations in the drive line. Hence achieving the NVH performance of AWD vehicles on par with FWD vehicles without any major change in the existing design is a major challenge. In this work, an AWD vehicle with severe body vibration and booming noise is studied. The operational measurements are taken throughout the drive train on all sub-systems from engine to the rear part of the body in the problematic operating condition. An operational deflection shape analysis is conducted to visualize the vibration behavior of the drive train. The result of analysis shows that the dynamic torsional fluctuations of the drive shaft and rear drive module (RDM) vibration are the major contributors for the high levels of vibration and noise.
Technical Paper
2014-04-01
Tae-il Yoo, Hanhee Park, Gubae Kang, Seongyeop Lim
Abstract Development of eco-friendly vehicles have risen in importance due to fossil fuel depletion and the strengthened globalized emission control regulatory requirements. A lot of automotive companies have already developed and launched various types of eco-friendly vehicles which include hybrid vehicles (HEVs) or electric vehicles (EVs) to reduce fuel consumption. To maximize fuel economy Hyundai-Kia Motor Company has introduced eco-friendly vehicles which have downsized or eliminated vibration damping components such as a torque converter. Comparing with Internal Combustion Engine(ICE) powered vehicles, one issue of the electric motor propulsion system with minimized vibration damping components is NVH (Noise, Vibration and Harshness). The NVH problem is caused by output torque fluctuation of the motor system, resulting in the degradation of ride comfort and drivability. Therefore, accomplishing both fuel economy and good NVH performance has become a significantly challenging task in eco-friendly vehicles.
Technical Paper
2014-04-01
Marcus Becher, Stefan Becker
Abstract This paper focuses on the applicability of numerical prediction of sound radiation caused by an axial vehicle cooling fan. To investigate the applicability of numerical methods, a hybrid approach is chosen where first a CFD simulation is performed and the sound radiation is calculated in a second step. For the acoustic simulation an integral method described by Ffowcs-Williams-Hawkings is used to predict the sound propagation in the far-field. The simulation results are validated with experiments. The corresponding setup in experiments and simulation represents an overall system which includes the cooler, the cooling fan and a combustion engine dummy. To optimize the economical applicability in terms of simulation setup and run time, different approaches are investigated. This includes the simulation of only one blade using a periodic boundary condition as compared to the whole fan geometry. In the CFD simulation an SAS-turbulence-model is applied. The results show that this is a very useful approach considering the challenges in prediction of numerical sound.
Technical Paper
2014-04-01
Manchi Venkateswara Rao, Jos Frank, Prasath Raghavendran
Abstract Accurate quantification of structure borne noise is a challenging task for NVH engineers. The structural excitation sources of vibration and noise such as powertrain and suspension are connected to the passenger compartment by means of elastomer mounts and spring elements. The indirect force estimation methods such as complex dynamic stiffness method and matrix inversion method are being used to overcome the limitations of direct measurement. In many practical applications, the data pertaining to load dependent dynamic stiffness of the connections especially related to mounts is not available throughout the frequency range of interest which limits the application of complex dynamic stiffness method. The matrix inversion method mainly suffers from the drawback that it needs operational data not contaminated by the effect of other forces which are not considered for calculation. In this paper, a new method is proposed in which the structure borne noise associated with powertrain is quantified easily and reliably.
Technical Paper
2014-04-01
Ajo John Thomas, Avnish Gosain, Prashanth Balachandran
Abstract The automobile market is witnessing a different trend altogether - the trend of shifting preference from powerful to fuel efficient machines. Certain factors like growing prices of fuel, struggling global economy, environmental sensitiveness and affordability have pushed the focus on smaller, efficient and cleaner automobiles. To meet such requirements, the automobile manufacturers, are going stringent on vehicle weights. Using electric and hybrid power-plants are other options to meet higher fuel efficiency and emission requirements but significant cost of these technologies have kept their growth restricted to only few makers and to only few regions of the globe. Optimizing the vehicle weight is a more attractive option for makers as it promises lesser time to market, is low on investment and allows use of existing platforms. However, lightweighting and NVH often conflict each other in vehicle development and hence design optimization plays a vital role in assigning a tradeoff between the lightweighting and NVH.
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