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2015-04-14
Technical Paper
2015-01-1667
Yasunori Kanda, Tsunehiro Mori
It has been required recently that diesel engines for passenger cars meet various requirements, such as low noise, low fuel consumption, high power and strict emission limits. The key to decrease the noise is to reduce a combustion noise known as “Diesel knock”. Conventional approaches to reduce the diesel knock are decreasing combustion excitation force due to pilot/pre fuel injection, adding ribs to engine blocks or improving noise transfer characteristics by using insulation covers. However, these approaches have negative effects, such as deterioration in fuel economy and increase in cost/weight. Therefore, modification of engine structures is required to reduce it. We analyzed noise transfer paths from a piston, a con rod, a crank shaft to an engine block and vibration behavior during engine operation experimentally, and identified that piston resonance was a noise source.
2015-04-14
Technical Paper
2015-01-1668
Chetankumar Patel, Nachiketa Tiwari, Avinash Kumar Agarwal
High viscosity of vegetable oil causes problems while using them as alternate fuel for compression ignition engines. There is a need to reduce the viscosity before using them as engine fuel. Preheating and pre-treating of vegetable oils using waste heat of exhaust gases is one of the techniques, which reduces the viscosity and makes it possible to use as alternate fuel for some niche applications, without major modifications in the engine hardware. There are several applications in developing countries such as decentralised power generation, agricultural engines, and water pumping engines, where vegetable oils can play a significant role as an alternate fuel. In present investigations, performance, combustion, emission characteristics of an engine using preheated Jatropha oil (J100) and 20% blend of Jatropha oil with mineral diesel (J20) have been evaluated at a constant speed (1500 rpm) in a single cylinder four stroke direct injection diesel engine.
2015-04-14
Technical Paper
2015-01-1669
Alexei P. Popov, George Nerubenko
Increasing challenges on reducing fuel consumption has opened the new directions in Automobile Powertrain technologies. The example of such technology implemented in geared transmission is the usage of novel type of gears with 3D point system of mesh engaging invented, patented and developed by Alexei P. Popov. The paper identifies the milestones of R&D that were undertaken to create the new type of geared transmission which could be used in vehicles. Using the Winkler hypothesis Alexei P. Popov had developed and designed new type of point contact which made possible to lower a contact stresses significantly in comparison to the values of a contact stresses for teeth having linear contacting interaction. The new profile and shape of tooth was invented and the methodological tools were developed for engineers providing the formulas for design and forming geometry of tooth with high stress capacity.
2015-04-14
Technical Paper
2015-01-1665
Nicolas Arnault, Adrien Baudet, Nicolas Becker
Vehicle integration in today society and especially in urban zones is the one of the main focus of regulators as well as car manufacturers. Indeed, vehicles impact on everyday life as air quality, noise, traffic density, urban spaces occupied by parked cars, among others is scrutinized and leads to at least significant efforts, but often to major improvements on all those topics. Noise is one of the key nuisances from which the car is the source. There are already some existing regulations, and they intend to become stricter and stricter. The perfect example of this trend is the recent new European Commission regulation adopted in April 2014, which requires a fair reduction of the allowable emitted noise, but may also introduce performance labels. Of course, there are solutions to deal with noise emissions.
2015-04-14
Technical Paper
2015-01-1674
Takashi Hoshi
For multi plate wet clutches in transmission systems, an understanding of the dynamic frictional characteristics of the friction surfaces and damping characteristics of the drivetrain are essential in predicting self-excited vibration. We made a test apparatus for torque transmission characteristics and measured the dynamic frictional characteristics of the friction surfaces at a uniform contact pressure. An understanding was gained of the changes in dynamic frictional characteristics due to temperature and contact pressure relating to the sliding velocity. We also obtained the damping characteristics by measuring the torque loss due to drivetrain friction. We created a clutch FEM model to gain a quantitative understanding of how to implement the dynamic frictional characteristics. Taking the damping characteristics of the drivetrain into consideration, we also made a plant model encompassing all areas from the transmission to the vehicle body.
2015-04-14
Technical Paper
2015-01-0667
Kei Ichikawa
The importance of reducing road noise is increasing . Methods that enhance acoustic sensitivity and reduce the force transferred from the suspension to the body are used to reduce road noise. Reduction of body suspension mounting point compliance has been used as a method of reducing acoustic sensitivity. There were cases where this method reduced acoustic sensitivity, the road noise pressure was not reduced; this study focused on the suspension transfer force and analyzed its mechanism of change using the Transfer Function Synthesis Method. The results showed that the balance between the body suspension mounting point, suspension bush and suspension arm tip compliance is an important factor influencing the change in suspension transfer force.
2015-04-14
Technical Paper
2015-01-0660
Kosuke Sakamoto, Toshio Inoue
When a vehicle is in motion, noise is generated in the cabin that is composed of multiple narrow-frequency bands from input from the road surface. This type of noise is termed low-frequency-band road noise, and its reduction is sought to increase occupant comfort. The research discussed in this paper used feedback control technology for the development of an active noise control technology able to simultaneously reduce noise in multiple narrow-frequency bands. We investigated methods of connecting multiple single-frequency adaptive notch filters, a type of adaptive filter. We tested a method of connecting multiple filters that mitigates mutual interference caused by different controller transmission characteristics. This method made it possible to implement controllers with amplitude and phase characteristics in multiple narrow-frequency bands corresponding to design values, and to achieve the target noise-reduction.
2015-04-14
Technical Paper
2015-01-0661
Jianwang Shao, Xian Wu, Na Wei, Ding Wang, Guoming Deng, Ming Xu
An increasing demand for vehicle noise control has been proposed and at the same time, vehicle weight and fuel economy have become critical for the automotive industry. The methodology of statistical energy analysis (SEA) is used to balance both light weight and high noise insulation performance. In this paper, the vehicle dash and floor sound package systems, which are two of the major paths for vehicle interior noise, are studied and optimized by CAE and testing technology. Two types of sound package which are the conventional insulation system and the lightweight one are chosen for the vehicle dash and floor system. The vehicle dash and floor systems are modeled by SEA and the transmission loss (TL) of the dash and floor system is analyzed, respectively. Several influence factors of the TL are also analyzed, such as sound package coverage, the leaks, etc.
2015-04-14
Technical Paper
2015-01-0662
Weiguo Zhang, Mac Lynch, Robert Reynolds
A turbocharger is currently widely used to boost performance of an internal combustion engine. Generally, a turbocharger consists of a compressor which normally is driven by an exhaust turbine. Both the compressor and the turbine will have an influence on how the low frequency engine pulsation propagates in the intake and exhaust system. In addition, the turbocharger will produce high frequency flow induced sound. The high frequency sound generation is associated with rotating blade pressures, supersonic tip speeds or rotating shock waves. This paper focuses on the application of computational fluid dynamics (CFD) to the prediction of this high frequency flow induced sound. A turbocharger compressor is generally a centrifugal compressor consisting of wheel, diffuser and housing. As the compressor wheel rotates, ambient air is drawn in axially through an air induction system, accelerated to high speed and then expelled in a radial direction to the outlet.
2015-04-14
Technical Paper
2015-01-0796
Stephen Busch, Kan Zha, Paul C. Miles, Alok Warey, Francesco Pesce, Richard Peterson, Alberto Vassallo
Various pilot-main injection strategies are investigated for a part-load operating point in a single cylinder optical Diesel engine. With a pilot injection energizing signal that is advanced from the main injection by 300 µs or more, a 9 dB reduction in combustion noise is achieved. It is observed that as the energizing dwell between a single pilot and the main injection is decreased below 200 µs, combustion noise passes through a minimum and a further reduction of 3 dB is possible. This additional decrease in combustion noise is not associated with increases in smoke or NOx emissions. The injection schedules employed in the engine are analyzed with a hydraulic injection analyzer to provide rate shapes for each of the dwells tested. Two distinct injection events are observed even at the shortest dwell tested, and various rate shaping effects are observed with the main injection event as the dwell is adjusted.
2015-04-14
Technical Paper
2015-01-1675
Yongfu Chen, Zhengfei Tang, Peijun Xu, Yunqing Zhang
A method for dynamic analysis and design of Powertrain Mounting System(PMS) is developed with the aim of reducing the vibration of the PMS, which is very significant to improve ride comfort. A nine degrees of freedom(DoF) dynamic model is established, including a powertrain and a chassis. The dynamic stiffness of the mounting is taken as the design parameter. Decreasing the dynamic force between the powertrain and the frame is the optimization objective. The initial values of the dynamic stiffness are obtained by finite element analysis. Due to the frequency dependence of dynamic stiffness, the dynamic stiffness is optimized at lower frequency section and high frequency section respectively. In addition, the deformation of the mounting under the gravity of powertrain is limited, which further determines the range of dynamic stiffness.
2015-04-14
Technical Paper
2015-01-1670
Can Tao, Hengjia Zhu, Peijun Xu, Yunqing Zhang
Hydraulic Engine Mount (HEM) is widely used in vehicle Powertrain Mounting System (PMS) for vibration isolation. The dynamic performances of an HEM are strongly frequency dependent. A Five-Parameters Fractional Derivative model is used to describe the dynamic properties of a HEM. A 1/4 and 1/2 car model are applied to evaluate the effect of frequency-dependent dynamic stiffness which using measured data of a typical hydraulic engine mount. The excitations from engine and road are considered in the simulation. The generalized- method is presented to solve the vehicle model with Five-Parameters Fractional Derivative model.
2015-04-14
Technical Paper
2015-01-0665
Yongchang DU, Yujian Wang, Pu Gao, Yingping Lv
Modelling of disc in brake squeal analysis is complicated because of the rotation of disc and the sliding contact between disc and pads. Many analytical or analytical numerical combined modeling methods have been developed considering the disc brake vibration and squeal as a moving load problem. Yet in the most common used complex eigenvalue analysis method, the moving load nature normally has been ignored. In this paper, a new modelling method for rotating disc from the point of view of modal is presented. First finite element model of stationary disc is built and modal parameters are calculated. Then the dynamic response of rotating disc which is excited and observed at spatial fixed positions is studied. The frequency response function is derived through space and time transformation. The equivalent modal parameter is extracted and expressed as the function of rotation speed and original stationary status modal parameters.
2015-04-14
Technical Paper
2015-01-1666
Lingzhi Li, Yimin Yang, Fengjun Zhao, Zhi Zhang, Hailong Cheng, Hangsheng Hou
An issue of engine squealing in low temperature range (around -25C) right after start-up emerged for a significant number of vehicles in a program. The squealing noise typically only lasted for a few seconds. The earlier effort had focused on typical common culprits such as the pulley-belt systems etc. However, much effort, by subjective listening, yielded no fruitful results for more than a year. The application of near-field acoustic holography on top of the engine in a climate chamber quickly identified several noise source locations. Further noise source identification on the top, front and left sides of the engine pinpointed the top three noise source locations: the idler pulley and the water pump on the front side, the air compressor on the right side, and the air intake throttle on the top. Then a series of experiments were conducted.
2015-04-14
Technical Paper
2015-01-0668
Yongchang DU, Pu Gao, Yujian Wang, Yingping Lv
The study and prevention of unstable vibration is a challenging task for vehicle industry. Improving predicting accuracy of braking squeal modal is of great concern. Closed-loop coupling disc brake model is widely used in complex eigenvalue analysis and further analysis. The coupling stiffness of disc rotor and pads is one of the most important parameters in the model. But in most studies the stiffness is calculated by simple static force-deformation simulation. In this paper, a closed-loop coupling disc brake model is built. Initial values of coupling stiffness are estimated from static calculation. Experiment modal analysis of stationary disc brake system with brake line pressure and brake torques applied is conducted. Then an optimization process is initiated to minimize the differences between modal frequencies predicted by the stationary model and those from test. Thus model parameters more close to reality are found.
2015-04-14
Technical Paper
2015-01-0216
Ping-Min Hsu, Ming Hung Li, Kuo-Ching Chang
This paper studies noise filtering in an autonomous emergency braking (AEB) system with a sensor fusion between a millimeter wave (MMW) radar and a camera. The AEB system may automatically brake cars by mistake due to the sudden appearance of noise signal if it does not involve any noise filtering mechanism for the object sensor. This may cause some accidents. To avoid such accidents, we propose the filters for three kinds of noise—named as twice harmonic noise, ground noise, and specular refection noise—which are commonly suffered while applying MMW radars. The former is caused by the reflection of a radar wave between a target object and the MMW radar. Based on the concern that the MMW radar evaluates the sensing distance based on the time interval between the transmitting and receiving of the radar wave, one of the sensing distances would be twice as longer as one of others due to the wave reflection. The object featuring this characteristic is further filtered.
2015-04-14
Technical Paper
2015-01-0666
Chenguang Li, Fue-sang Lien, Eugene Yee, Mike Dong
A deeper understanding of the complex phenomenology associated with the flow induced noise and vibration in a dynamic valve is of critical importance to the automotive industry. To this purpose, a two-dimensional axisymmetric numerical model has been developed to simulate the complex processes that are responsible for the noise and vibration in a poppet valve (or poppet). More specifically, an Eulerian multiphase flow model, a dynamic mesh and a user-defined function are utilized within the ANSYS-FLUENT software system in order to facilitate the modeling of the complicated two-phase fluid-structure interaction problem associated with the generation of noise and vibration in a poppet valve. In this strongly coupled simulation framework, the poppet valve which is driven by spring and various dynamical fluid forces (e.g., viscous and pressure forces), is modeled as an under-damped vibration system.
2015-04-14
Technical Paper
2015-01-1671
Mohamed El-Morsy, Gabriela Achtenova
In this paper, a fault in rolling bearing is diagnosed using time waveform analysis. In order to verify the ability of time waveform analysis in fault diagnosis of rolling bearing, an artificial fault is introduced in vehicle gearbox bearing: an orthogonal placed groove on the inner race with the initial width of 0.65 mm approximately. The faulted bearing is a roller bearing located on the gearbox input shaft – on the clutch side. An optimal Morlet Wavelet Filter and autocorrelation enhancement are applied in this paper. First, to eliminate the frequency associated with interferential vibrations, the vibration signal is filtered with a band-pass filter determined by a Morlet wavelet whose parameters are optimized based on maximum Kurtosis. Then, to further reduce the residual in-band noise and highlight the periodic impulsive feature, autocorrelation enhancement is applied to the filtered signal.
2015-04-14
Technical Paper
2015-01-1329
Katsutomo Kanai, Hideki Katsuyama
We developed a method of predictive simulation of flow-induced noise using computational fluid dynamics. Because the goal was to employ the method in the automotive development process, development sought to balance practical predictive accuracy and computation time. In order to simulate flow-induced noise, detailed eddy flows and changes in the density of the air must be computed. In the development discussed in this paper, we conducted unsteady-state compressible computations using large eddy simulation, a type of turbulence modeling, to predict whether flow-induced noise would occur. The target flow-induced noise was narrow-band noise, also known as whistling noise, a type of noise that increases in a specific frequency range. The target area of generation of flow-induced noise was set as the exhaust pipe, which incorporates the complex shape of the muffler.
2015-04-14
Technical Paper
2015-01-1673
Seunghyun Lee, Kyoungdoug Min
In this study, the correlation between the maximum heat release rate and the vibration of the diesel engine block was derived, and a methodology for determination of maximum heat release rate was presented. In order to investigate and analyze the correlation, the bench test and the real road vehicle test were carried out with a 1.6 l diesel engine. By varying the engine speed, load and main injection timing, the vibration signals were measured on engine block and was analyzed through continuous wavelet transform. It is shown that the maximum heat release rate had stronger correlation with magnitude of vibration rather than peak in-cylinder pressure and maximum in-cylinder pressure rise. A specific bandwidth, vibration signal of 0.1~2 kHz, was affected by the variation of heat release rate. The vibrations excited by combustion were lasted over 50 CAD, however, the signals in period of 35 CAD after start of injection had dominant effect on maximum heat release rate.
2015-04-14
Technical Paper
2015-01-0831
Wonah Park, Youngchul Ra, Eric Kurtz, Werner Willems, Rolf D. Reitz
The low temperature combustion concept is very attractive for reducing NOx and soot emissions in diesel engines. However, it has potential limitations due to higher combustion noise and CO and HC emissions. A multiple injection strategy is an effective way to reduce unburned emissions and noise in LTC. In this paper, the effect of multiple injection strategies was investigated to reduce combustion noise and unburned emissions in LTC conditions. A hybrid surrogate fuel model was developed and validated, and was used to improve LTC predictions. Triple injection strategies were considered to find the role of each pulse and then optimized. The split ratio of the 1st and 2nd pulses fuel was found to determine the ignition delay. Increasing mass of the 1st pulse reduced unburned emissions and an increase of the 3rd pulse fuel amount reduced noise. It is concluded that the pulse split ratio can be used as a control factor for emissions and noise.
2015-04-14
Technical Paper
2015-01-1309
Hyunggyung Kim
This paper describes about the development of new concept’s rear wheel guards for the reduction of Road Noise in the passenger vehicle using test. The new wheel guards are proposed by various frequency chamber concept and different textile layers concept. Two wheel guards were verified by small cabin resonance test and vehicle test. Through new developing process without vehicle test, Result of road noise will be expected when new concepts and materials of wheel guard is applied into automotive vehicle. As this concept consider tire radiation noise frequency and multilayers sound control multilayers, 2 concepts reduced road noise from 0.5 to 1.0 dB The suggested Estimation method of part reverberant absorption method is similar to result of vehicle tests by part absorption index. Furthermore, optimization of frequency band to wheel guards will reduce more 0.5 dB noises in vehicle.
2015-03-30
Technical Paper
2015-01-0106
Zhe Yu, Wenjie Qin, Qingdong Hou, Mu Tang, Yang Ran
Wiper noise generated in the process of wiping is one of the main influence factors affecting the driving comfort. Since the dynamic pressure of the contact between a blade and a windshield glass is difficult to be simulated or measured, which make it is extremely particularly difficult to predicte the degree of the wiper noise. To solve this problem, in this paper, as the reversal noise problem of a passenger-vehicle windscreen wiper system is concerned, the system dynamic models of the both wipers on the sides of the driver and copilot were built on the basis of consideration of the blade deformation and the elastic contact between the blades and the windscreen glass, which including the crank pivot, the four linkage mechanism, the wiper blades, the wiper arms and the windscreen glass.
2015-03-30
Technical Paper
2015-01-0108
Qingdong Hou, Wenjie Qin, Zhe Yu, Mu Tang, Yang Ran
With the increasing of ride comfort requirements for modern vehicles, the noise generatingbefore and after the windshield wiper reverses direction becomes more noticeable.In this paper,the impacts of some factors---the preload of wiper lever spring, the torsional stiffness of blade neck and the flexible connection between the wiper arm and the wiper lever on the vibration excitation appliedto the front windshield are analyzed based on the multi-body dynamic modelof wiper system (includingthe crank pivot, the four linkage mechanism, the wiper blades, the wiper arms and the windscreen glass) which has been established by taking elastic contact between the wiper blade and the front windshieldinto consideration.
2015-03-30
Technical Paper
2015-01-0107
Sunny Narayan
Analysis of noise level from engines is important from point of view of customer satisfaction .Accurate prediction of noise is important for planning,design and target setting decisions for meeting customer satisfaction goals.In this work an analytic model has been described to break diesel engine noise data into various components in order to plan a strategy for condition monitoring of engine.
2015-01-14
Technical Paper
2015-26-0122
Herman Van der Auweraer, Karl Janssens, Fabio Bianciardi, Filip Deblauwe, Kumaraswamy Shivashankaraiah
Abstract Certification of vehicle noise emissions for passenger vehicles, motorcycles and light trucks is achieved by measuring external sound levels according to procedures defined by international standards such as ISO362. The current procedure based on a pass-by test during wide-open throttle acceleration is believed far from actual urban traffic conditions. Hence a new standard pass-by noise certification is being evaluated for implementation. It will put testing departments through their paces with requirements for additional testing under multiple ‘real world’ conditions. The new standard, together with the fact that most governments are imposing lower noise emission levels, make that most of the current models do not meet the new levels which will be imposed in the future. Therefor automotive manufacturers are looking for new tools which are giving them a better insight in the Pass-by Noise contributors.
2015-01-14
Journal Article
2015-26-0136
Deepak Mahajan, Arnab Sandilya, Lokesh Khandelwal, Sameer Srivastava
Abstract Automotive floor carpet serves the purpose of insulating airborne noises like road-tire noise, transmission noise, fuel pump noise etc. Most commonly used automotive floor carpet structure is- molded sound barrier (PE, vinyl etc.) decoupled from the floor pan with an absorber such as felt. With increasing customer expectations and fuel efficiency requirements, the NVH requirements are increasing as well. The only possible way of increasing acoustic performance (Specifically, Sound Transmission Loss, STL) in the mentioned carpet structure is to increase the barrier material. This solution, however, comes at a great weight penalty. Theoretically, increasing the number of decoupled barrier layers greatly enhances the STL performance of an acoustic packaging for same weight. In practice, however, this solution presents problems like- ineffectiveness at lower frequencies, sudden dip in performance at modal frequencies.
2015-01-14
Technical Paper
2015-26-0134
Jayant Sinha, Ajit Kharade, Shrihari Matsagar
Abstract An interior sound quality is one of the major performance attribute, as consumer envisage this as class and luxury of the vehicle. With increasing demand of quietness inside the cabin, car manufactures started focusing on noise refinement and source separation. This demand enforces hydraulic power steering pump to reduce noise like Moan and Whine, especially in silent gasoline engine. To meet these requirements, extensive testing and in-depth analysis of noise data is performed. Structured process is established to isolate noises and feasible solutions are provided considering following analysis. a) Overall airborne noise measurement at driver ear level (DEL) inside the cabin using vehicle interior microphone.b) Airborne and Pressure pulsation test by sweeping pump speed and pressure at test bench.c) Waterfall analysis of pump at hemi anechoic chamber for order tracking and noise determination.
2015-01-14
Technical Paper
2015-26-0132
Ajay Paul John, Vikas Kumar Agarwal, Prashant Bhavsar
Abstract High fuel efficiency, low ownership/ maintenance cost and favorable driving climate are the major reasons for the increasing demand for low-power commuter motorcycles and scooters, particularly in developing countries like India, Brazil and China. Noise Vibration and Harshness (NVH) has now become a new subject for the battle between competing manufacturers in attracting customers. Valvetrain noise is quite significant in the engines of these cost gasoline vehicles as they don't incorporate a Hydraulic Lash Adjuster (HLA) to keep the manufacturing costs less. The aim of this study was to understand how the cam ramp velocity and height affects the noise generated by the engine and what effect they have on its performance.For this study, a small scooter gasoline engine with an Over Head Camshaft (OHC) and a rocker arrangement with a roller-follower was considered.
2015-01-14
Technical Paper
2015-26-0137
Himanshu Agrawal, Abhishek Arun Kakade, Arun Kumar Singh, Sandeep N Shetty
Abstract Fan is generally used for cooling of alternator and an undesirable side effect of these fans is generation of flow induced noise. With stricter regulations and growing importance on acoustic comfort in present day market, it's very important to address flow induced noise problems early in product development stage. With physical testing, it would not be possible to get information on source strengths thus, limiting its usage. Whereas simulation on the other hand would be able to provide source strengths, directivity pattern and source ranking. This paper focuses on numerical simulation of alternator's fan for prediction of air- borne noise. For this purpose, Computational Fluid Dynamics (CFD) based transient analysis is performed with high fidelity turbulence model using commercial software package, ANSYS Fluent. Ffowcs Williams and Hawkings (FW-H) model is used for modeling sound propagation.
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