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Technical Paper
2014-11-11
Andrea Fioravanti, Giulio Lenzi, Giovanni Vichi, Giovanni Ferrara, Stefano Ricci, Leonardo Bagnoli
The intake and exhaust lines are the main elements contributing to the abatement of the acoustic emissions of an Internal Combustion Engine (ICE). Many different numerical approaches can be used to evaluate their acoustic attenuation, which is commonly expressed by the Transmission Loss. One-dimensional (1D) and three-dimensional (3D) simulations are conventionally carried out only within the acoustic domain of the muffler or the air-box. The walls of the acoustic filter are considered fully rigid and the interaction between the acoustic waves and the structure is then neglected. Moreover, the effect of the manufacturing characteristics and the attenuation of the acoustic waves due to the fluid viscothermal effects are also commonly disregarded in the numerical analysis of the filters. In addition the presence of a catalytic converter or a filter cartridge may have an influence on the numerical results. All these aspects, however, can remarkably affect the matching between simulations and experiments both at high frequencies and also at medium-low ones.
Technical Paper
2014-11-11
Kazuhiko Tanaka, Haruomi Sugita, Hibiki Saito, Masahiko Sekita
The exhaust sound of a motorcycle is one of the key appealing factors to the customers along with its styling and dynamic performances. Accordingly, various attempts have been made to realize attractiveness of exhaust sounds. Recently, there is an increasing demand to divert a common motorcycle engine to various vehicle categories. An individual engine configuration category has its own featuring exhaust sound. Despite of these circumstances, it is also required to create the best suitable sound for each vehicle category with a specific vehicle feature. Accordingly, there is a possible case in which an inline-four-cylinder engine is shared with another motorcycle model in the vehicle category with nostalgic appearances in which V-twin engine flavor is frequently featured. In this study, three essential factors were extracted from the verbal expressions that appear as adjectives, exclusively or commonly, used to illustrate the exhaust sounds in each vehicle category or engine type. We tried to develop a method applicable to various engine types to design a targeting exhaust sound, by clarifying the relationship between the position of each exhaust sound, appeared on the mapping chart for the three factors, and the feature of the waveform of the sound,.
Technical Paper
2014-11-11
Thomas Metzinger, Christoph Raber, Christoph Wittmann
20th Small Engine Technology Conference “New development approach for wet motorcycle clutch systems” The change of the motorcycle market in the last decade ask for “solutions” for the changed requirements. The strong rising bike segment of the emerging markets characterized by one cylinder engines up to 250ccm and 25HP and a focus of low price range of the vehicle in combination with a high sales volume. These bikes normally daily used for individual transportation. On the other side you have the bike segment of the industrial countries in which the bikes used mainly for hobby purposes or as amateur bike racer. The sales volume of these segment consolidated in the last years and have several subgroups like sport bike, touring, off-road and others. All of the segments and subgroups have their individual requirements to the clutch system. Now Schaeffler combine their experience in developing and producing components for small engines and clutch systems for the automotive sector to develop the ideal clutch system for a motorbike.
Technical Paper
2014-11-11
Gabriele Benigni, Antonio Agresta, Francesca Di Puccio, Paola Forte
NVH simulations for an automotive component industry represents a convenient mean to compare different solutions and make decisions on design choices based on the predictions of the component vibro-acoustic behavior. This paper presents the work carried out by the Modeling & Simulation Department of Continental Automotive Italy Spa in cooperation with LMS Italy Srl and the Department of Civil and Industrial Engineering of University of Pisa aimed at the vibro-acoustic characterization and comparison of two fuel rails assemblies (FRAs) by mean of simulations in Ansys Workbench & LMS Virtual.Lab. These simulations required a preliminary finite element (FE) modal analysis on the FRAs. To verify the reliability of the FE models, an experimental modal analysis was performed on one of the two fuel rails in free condition. The correlation between FE and test models highlighted some differences: a sensitivity study proved that the differences depend on the modeling of some brazed joints. The results of the following NVH simulations were checked by performing an acoustic impact test on the two FRAs in free condition inside an anechoic chamber.
Technical Paper
2014-11-11
Sara Gronchi, Riccardo Maccherini, Raffaele Squarcini, Fabio Guglielmo, Emanuela Ligarò
In the modern both small and large size engine, the acoustic emission is a very important matter increasingly studied as per specific international standards. This paper presents the study of the acoustic emission of a hydraulic rotary oil pump by means of measurement techniques and numerical approaches. This activity aims at showing a complete test-case in which both methods are used to face a noise issue and highlighting also the “weight” of the hydraulic excitation in both cases. In particular, an oil pump has been completely characterized on a test bench to verify the hydraulic performances and the noise radiation. A structural modification has been suggested with the target of altering the noise spectrum of the pump, achieving an optimization of the noise generation. From this assumption, experimental and numerical activities have started in parallel. Measurements have been carried out by means of the intensimetric method and supported also by conventional acquisitions performed with hydraulic pressure transducers, accelerometers and microphones.
Technical Paper
2014-11-11
Vishnu Kumar Kuduva Shanthulal, Kannan Marudachalam, V Pattabiraman, S Jabez Dhinagar, Chandramouli Padmanabhan
The diesel power train (engine and transmission) is the most significant mass contributor in a three- wheeled vehicle. High idling vibrations of a single cylinder four-stroke diesel engine causes discomfort for driver and passengers as vibrations from the engine get transmitted to the structure and the body panels through the engine mounts. The isolation of these vibrations by proper design of rubber mounts is the most effective engineering approach to improve ride quality of vehicle. In the present study, a mathematical model of the powertrain and mount system is developed; the engine and transmission are assumed to behave as a rigid body (6 degrees-of-freedom) and the compliance comes from the mounts. Both four and three mount configurations have been investigated, with the mounts being represented by three independent springs in the compression and shear modes. Since the mounts can be inclined, appropriate transformations are carried out from the local mount co-ordinate system to the global co-ordinate system.
Technical Paper
2014-11-11
Diego Copiello, Ze Zhou, Gregory Lielens
This paper addresses the numerical simulation of vehicle exhaust system noise using an innovative transfer matrix method (TMM) supporting high order duct modes combined with finite element method (FEM). Exhaust systems usually consist of complex volume components (mufflers, catalyzers ...) connected by simpler pipes. The noise propagation through such systems can be efficiently addressed by means of the Transfer Matrix Method (TMM). The TMM is an analytical method which allows assessing efficiently the acoustic behavior of an entire exhaust line by combining acoustic transfer matrices of each of its constitu¬ent sub-components (i.e., volume components: mufflers, catalyzers, etc.). The main assumption of this method is that within the exhaust line only the plane wave is propagating and thus the transfer matrices could be computed analytically. On the contrary, this assumption leads to a strong limitation in the maximum frequency of analysis which is the cut off frequency of the first higher order mode present in any one of the exhaust line components.
Technical Paper
2014-10-13
Jouji Kimura, Shinichiro Kobayashi, Katsuhiro Hoshina, Kousuke Kawase, Koji Matsui, Atsushi Yamamoto
This paper describes the characteristics and mechanism of crankshaft impact noise that radiates from the cylinder body at full load medium engine speeds, based on the mechanism for axial vibration of crankshaft coupled with torsional vibration of crankshaft. Crankshaft Impact noise (hereinafter referred to as ‘impact noise’) is heard as an intermittent noise from the front of the 6-cylinder in-line engine at the full load engine speeds from 1000rpm to 1500rpm, predominant at 1200rpm, and the impact noise frequency ranges from 1.5 kHz to 3.5 kHz. The following steps were taken to prove that impact noise is caused by an axial vibration of crankshaft coupled with a torsional vibration of crankshaft. Firstly, impact noise was heard from the engine front, and thus the noise at a distance of one meter from the engine front, the vibrations on the cylinder body at No.1 crank-journal center and the crank angle were measured at a full load speed of 1200 rpm. In the measurement, the large vibrations (hereinafter referred to as ‘impact vibration’) were detected three times per two rotations of crankshaft at about 50° after the firing top dead centers (50° ATDC) of No.1, No.3 and No.2 cylinders, and impact noise was detected at a crank angle of about 50°ATDC of No.1 cylinder and at this angle, the impact vibration was the largest.
Technical Paper
2014-10-13
Anandan Sivakumar, V. Saishanker, Raghvendra Gopal
Success of the vehicle in cold countries depends on performance of the vehicle under cold climatic conditions. In automobiles, structural elastomer components have strong influence on vehicle performance including NVH, ride comfort & durability. Elastomers are sensitive in nature to these climatic conditions due to its temperature dependent visco-elastic behavior. Thus, it is very important to understand structural elastomer component's performance at sub zero temperatures. In a vehicle Engine mount is used to hold engine firmly and isolate vibrations away from chassis. Vibration isolation of a mount at low temperature is generally affected by the rubber composition. Major ingredients of the rubber composition influencing the low temperature characteristics are Elastomer type, filler type, plasticizer and curing system. Rubber composition plays key role in achieving engine mount properties like static stiffness, dynamic stiffness, permanent set and durability. In this work, influence of low temperature has been successfully evaluated for engine mount application by varying elastomer type, filler type, plasticizer and curing system.
Technical Paper
2014-10-13
Yuan Fang, Tong Zhang
Because of the vehicle market competitive and of the raise of customers’ demanding, NVH performance became an important job, especially for new energy vehicles. As the electric vehicle moving into the direction of high speed and large torque, electric vehicle vibration and noise problems highlighted gradually. In recent years, CAE has played an increasing role in the design ,development and optimization of powertrain NVH at component and system levels. The subject of this paper was the numerical and experimental evaluation of the electromagnetic and vibro-acoustic behavior of an electric powertrain. For this purpose, a coupled and fully flexible dynamics model of the electric powertrain was developed. Then electromagnetic forces including both radial and tangential force and gear mesh excitations including time-varying meshing stiffness, meshing error and meshing impact were computed, which were used to perform forced response analysis on the full FE mesh of the powertrain housing. An experimental bench was used to test the vibration acceleration and radiation noise of the electric powertrain in semi-anechoic room.
Technical Paper
2014-10-13
Zhiyong Chen, Zhiyuan Chen, Yang Mao, Wenku Shi, Guihui Zhang
To research the torsional vibration damping characteristic of magneto-rheological fluid dual mass flywheel (MRF-DMF) and the control system in drive train, the multi-degree power train torsional vibration model which contains MRF-DMF and fuzzy control model are built, then the damping characteristic of MRF-DMF in several conditions are gained and compared with MRF-DMF when no control system. The result indicates: the damping characteristic of MRF-DMF effect on power train when using control is better than without control in idle, speed up, slow down, ignition and stalling, while the damping characteristic is less obvious in constant speed because the simulation condition and damping moment relatively stable.
Technical Paper
2014-10-13
Zhi-yong Chen, Ning Sun, Wenku Shi
In order to improving structure and performance of magneto-rheological dual mass flywheel (MRF-DMF), some parameters effects on dynamic characteristics are acquired by parameters analysis. The dynamic stiffness and loss angle in different current and different frequency are gained through dynamic characteristic test. The fluid-structure interaction finite element model of MRF-DMF is built and the accuracy is verified by comparison between test and simulation. Based on the model , the parameters analysis is done and the law of MRF viscosity、 arc spring stiffness, working clearance, rotor radius and axial width effect on dynamic characteristics are gained, it will prove some guidance for the structure and performance improvement.
Technical Paper
2014-10-13
Georg Johann Meingaßner, Hermann Pflaum, Karsten Stahl
Downsizing and downspeeding are currently important development approaches of the automobile industry to improve fuel efficiency and to reduce emissions. Decreased operational speeds in combination with higher combustion pressures lead to an increase of the excitation of torsional vibrations by the combustion engine. Torsional vibrations in powertrains can cause strength and NVH problems as well as lower the driving comfort and reliability of the vehicle. Simultaneously, increasing customer demands for operating smoothness and driving performance additionally exacerbate the requirements. Currently the conventional systems for reduction of torsional vibrations, e.g. dual mass flywheels, are increasingly reaching their limits. In cooperation of three institutes of the Technische Universität München (TUM) innovative concepts for an improved reduction of torsional vibrations in automotive powertrains have been developed ([1], [2], [3], [4], [5]). Several of those concepts have been realized as prototype assemblies engineered by the Gear Research Centre (FZG).
Technical Paper
2014-10-13
Daniela Siano, Fabio Bozza, Luigi Teodosio, Vincenzo De Bellis
This paper reports 1D and 3D CFD analyses aiming to improve the gas-dynamic noise emission of a downsized turbocharged VVA engine through the re-design of the intake air-box device, consisting in the introduction of external or internal resonators. Nowadays, modern SI ICEs show more and more complex architectures that, while improving the brake specific fuel consumption (BSFC), may be responsible for the increased noise radiation at the engine intake mouth. In particular VVA systems allow for the actuation of advanced valve strategies that provide a reduction in the BSFC at part load operations thanks to the intake line de-throttling. In these conditions, due to a less effective attenuation of the pressure waves that travel along the intake system, VVA engines produce higher gas-dynamic noise levels. The worsening of the engine gas-dynamic performance can be compensated with a partial re-design of the air-box device, without significantly penalizing the engine power output. In order to find new design configurations of the air-box device capable of improving the noise levels, different numerical models can be successfully employed.
Technical Paper
2014-10-13
Harald Stoffels, Kay Hohenboeken
The impact of the number of cylinders on two downsized gasoline engines on driving habits in the same passenger-vehicle type was investigated. This was carried out with two similar vehicles, equipped with an in-line three cylinder (i3) and an in-line four cylinder engine, both having same power, torque and transient-response behaviour. Both engine types were mated to six-speed manual transmissions with same gear-ratios and dual-mass flywheel characteristics. The study was performed by letting 21 subjects driving the same route and both vehicles consecutively. The relevant data during driving were recorded simultaneously from either vehicle integrated sensors (CAN), and secondary transducers. We found that the in-line three cylinder was operated at higher engine speeds even though it was operated at similar acceleration- and load levels like the in-line four cylinder power-train, whereat the off-set of the engine speed shows no correlation with the difference in firing frequency between both engine types.
Technical Paper
2014-09-30
Anatoliy Dubrovskiy PhD, Sergei Aliukov, Yuriy Rozhdestvenskiy PhD, Olesya Dubrovskaya, Sergei Dubrovskiy
At present, we have developed a fundamentally new design of adaptive suspension systems of vehicles. Their technical characteristics and functional abilities are far better than the existing designs of suspensions. We have developed the following main suspension components of vehicles: a lockable adaptive shock absorber with an ultra-wide range (hyper range) of control performance, implementing "lockout" mode by means of blocking adaptive shock absorber, and an elastic element (spring, torsion, and so on) with progressive non-linear characteristic and automatic optimization of localization of work areas. Our design has no analogues in the practice of modern transport engineering. Our patents confirm the novelty and efficiency of our major design decisions. Advantages of our developments in the vehicle suspensions are the following: Firstly, it should be noted that when the vehicle is in a wide range of speeds in a so-called "comfort zone", we were able, by applying the non-linear elastic element, to reduce significantly the stiffness of the elastic suspension elements in compare with the regular structures - at least in two times!
Technical Paper
2014-09-30
Xianjian Jin, Guodong Yin, Youyu Lin
Knowledge of vehicle dynamics variables is very important for vehicle control systems that aim to improve handling characteristics and passenger safety. However for both technical and economical reasons some fundamental data (e.g., Lateral tire-road forces and vehicle sideslip angle) are not measurable in a standard car. This paper proposes a novel Interacting Multiple Model Filter-Based method to estimate lateral tire-road forces by utilizing real-time measurements. The method uses measurements (yaw rate, roll rate, accelerations, steering angle and wheel speed) only from sensors which have already been integrated in modern cars. The estimation method of lateral tire-road forces is based on an interacting multiple model (IMM) filter that integrates in-vehicle sensors of in-wheel-motor-driven electric vehicles to adapt multiple vehicle-road system models to variable driving conditions. Considering extended roll dynamics and load transfer, a four-wheel nonlinear vehicle dynamics model (NVDM) is built.
Technical Paper
2014-09-30
Venkatesan C, Mohan Rao
Durability of components plays a major role in the total cost of ownership of a commercial vehicle. The powertrain mount is one such component which is constantly at work in a vehicle and its rubber characteristics play a major role in the NVH and Life of the component. This paper presents the enhanced durability benefits obtained by changing the polymer composition, manufacturing methods and design optimization of a powertrain mount. The methodology involved characterization of the existing mount, arriving a new compound formulation, making of prototypes, experimental validation for durability and repeatability in the laboratory combined with rigorous on field vehicle trials. NVH measurements were also carried out on the improved mounts. The above exhaustive exercise resulted in the development of a comprehensively far better mount than an existing mount with improved durability without compromise on NVH properties. The cost benefit in terms of the total vehicle life was enhanced to a large extent.
Technical Paper
2014-09-30
John Stuart, Stefano Cassara, Brendan Chan, Nicholas Augustyniak
Wobble and shimmy vibrations are commonly observed in commercial highway vehicles with solid-beam front axles. These vibrations are typically self-excited and manifest themselves as sustained oscillations about the kingpin and axle tramp. A study was initiated to investigate and quantify wobble and shimmy behaviors, with a primary focus on wobble. A cross functional team including test and simulation engineers evaluated a vehicle exhibiting these behaviors. The team developed an ADAMS model to reproduce the behaviors and developed a DOE to quantify the impact of variables and combinations of variables. The evaluation demonstrated that dynamic imbalance in the rotating masses is a primary source of excitation. Wheel run-out, caster angle, tire brand, tire wear and tire inflation are also significant sources. Future studies will use these findings to mitigate the concern.
Technical Paper
2014-09-30
Masahiro Akei, Takayuki Koizumi, Nobutaka Tsujiuchi, Takayuki Yamauchi
Abstract This paper describes a prediction of vibration and the transfer path analysis (TPA) using an engine multi body dynamics (MBD) model and measured frequency response functions (FRFs). TPA is used in order to analyze each contribution of vibration transfer paths. In the TPA, input forces from vibration source to passive part should be identified accurately. In the traditional TPA, an identification of input forces is done using only experimental results. Therefore, a parametric study to an improvement of a structure or an isolation system is impossible. In this study, the MBD model of engine is constructed, and input forces from engine to mainframe of agriculture machine are predicted. The accuracy of prediction is confirmed, compared with the results from the traditional TPA method. The contribution of each transfer path is analyzed, and the vibration levels of operator position are predicted using the measured FRFs and the simulated input forces. As a result, the input forces and the vibration levels of operator position can be predicted accurately.
Technical Paper
2014-09-30
John Anderson
Abstract This paper describes the development and testing of a Dynamic Vibration Absorber to reduce frame beaming vibration in a highway tractor. Frame beaming occurs when the first vertical bending mode of the frame is excited by road or wheel-end inputs. It is primarily a problem for driver comfort. Up until now, few options were available to resolve this problem. The paper will review the phenomenon, design factors affecting a vehicle's sensitivity to frame beaming, and the principles of Dynamic Vibration Absorbers (AKA Tuned Mass Dampers). Finally, the paper will describe simulation and testing that led to the development of an effective vibration absorber as a field fix.
Technical Paper
2014-09-30
Rahul Ramola, G Senthilkumar, P Kannan, Muralidharan Chennakrishnan
Abstract The demand for comfort level in commercial vehicles is steadily increasing. Hence, fine-tuned performance parameters and attributes are required to fulfill the expectations from these vehicles. Refinement of noise and vibration without affecting performances of sub-systems and components has become extremely challenging with increasing customer requirements. This paper presents an approach to identify and reduce the high level whistling noise that was perceived in the passenger compartment while the vehicle was accelerated above 50 kmph. Interior noise measurements in static engine run-up condition reveal that the whistling noise is of specific order. Since, whistling noise is related to aerodynamic response of components, engine cooling fan, turbo charger, alternators and compressors were suspected. Using order tracking and near field measurements, HVAC alternator was confirmed as the main cause for whistling noise. Noise measurements confirmed that orders related to alternator cooling fan became dominant above 50 kmph.
Technical Paper
2014-09-30
Masahiro Akei, Takayuki Koizumi, Nobutaka Tsujiuchi, Takayuki Yamauchi
Abstract This paper describes an identification of a sound source model for a diesel engine installed on an agricultural machine by Inverse-Numerical Acoustic analysis (INA), and the applicability of the identified sound source model. INA is a method to identify surface vibrations from surrounding sound pressures. This method is applicable for a complicated-shaped sound source like an engine. In order to confirm the accuracy of the identified sound source model, the surface vibrations of the engine are compared with the measured results. Moreover, in the condition of the simulated engine room, the surrounding sound pressure levels of the engine are predicted using the sound source model and the boundary element method (BEM). For the verification of the prediction accuracy, the surrounding sound pressures of the engine are measured using the testing device which simulated actual engine room, namely an enclosure. As a result, the sound source model of the diesel engine is identified accurately using the INA.
Technical Paper
2014-09-28
Kun Diao, Lijun Zhang, Dejian Meng
As a complicated phenomenon of friction-induced noise, brake frictional squeal has remained a challenge to automotive industry. So far, the generation mechanism of brake squeal has not been made clear, and the effective control measures have not been established. But the previous researchers found that the brake frictional squeal showed the time-varying characteristic obviously, but did not pay enough attention on it. In this paper, to avoid too many difficulties, which are caused by complex structures and numerous impact factors of brake system, a pin-on-disc system was established to study the generation mechanism and key impact factors of frictional squeal to investigate the time-varying characteristic of brake frictional squeal. In this paper, a series of tests on pin-on-disc system was carried out to study the time-varying frictional squeal. Through the frictional squeal rig test, brake frictional squeals were produced repetitively. During the rig test the frictional squeal, the contact forces and the acceleration of the pin end were sampled under various speed and loading force conditions, and the wavelet analysis, time-frequency analysis and feed-in energy calculation methods were used to investigate the time-varying characteristic of frictional squeal.
Technical Paper
2014-09-28
SeongJoo Lee, JooSeong Jeong, ShinWook Kim, ShinWan Kim, Seong Rhee
A previous investigation showed that minor variations in alloying elements in gray cast iron disc contributed to measurable differences in friction and disc wear. This investigation was undertaken to find out if and how the increased friction and disc wear might affect brake squeal. The SAE J2522 and J2521 dynamometer procedures as well as an OEM noise dynamometer procedure and a chassis dynamometer noise procedure were used to find out if a correlation between disc wear and brake squeal could be discovered. In all cases, as the wear rate of a disc increases under a given set of test conditions, disc material transfer to the pad surface increases, which results in increased friction and brake squeal. Also a good method to detect disc variability (disc to disc, within a disc) is discussed.
Technical Paper
2014-09-28
Nils Gräbner, Merten Tiedemann, Utz Von Wagner, Norbert Hoffmann
Abstract Industry and academia agree that brake squeal is a nonlinear phenomenon. Consequently, using solely linear finite-element (FE) models and assessing the tendency of a brake system to squeal exclusively on the stability of the trivial solution is not appropriate. However, the latter approach - in the brake community known as complex eigenvalue analysis (CEA) - is extensively used in industry. Until now, nonlinear simulation approaches considering existence and stability of periodic solutions are mostly limited to minimal models. Among the variety of reasons for this the complexity of large-scale nonlinear models as well as the identification of nonlinear material and system parameters are crucial. This contribution discusses the relevance of nonlinearities in friction brake noise, vibration, harshness (NVH) and presents a novel simulation approach for brake squeal. On the basis of experimental results it is pointed out that the consideration of nonlinearities in simulation as well as new methods for numerical studies are necessary to cope with the system-inherent phenomena.
Technical Paper
2014-09-28
Katsuhiro Uchiyama, Yuji Shishido
Abstract Last year, we presented the “spring - mass model” FEA simulation from stick-slip phenomenon standpoint for improvement of “creep groan”. “Creep groan” is one of representative groan of brake system for automobile and it is clarified by µ vs velocity (µ−V) property of friction material. This time, we will present our study for reduction of creep groan by pad shape parameter (chamfer and slot) with “advanced” spring - mass model” FEA simulation which used actual pad shape as mass model. In addition, this paper was revised based on oral presentation which we presented at SAE 2013.
Technical Paper
2014-09-28
Taeho Jung, Jeongkyu Kim
Abstract Rust accumulated on disc surfaces causes brake judder and grind noise. This paper deals with grind noise(wire brush brake noise) in vehicles which is a low frequency vibration and broadband noise problem at 100∼1kHz that appears in low vehicle speed. Recently, the customer complaints have increased for grind and creep groan noise more than squeal noise. Low frequency brake noise is a combined effect of brake and suspension systems working with each other. The noise transfer path is also important. Experimental results are confirmed through ODS, Modal, TPA and 3D acoustic camera for noise transmission path. Finally, reduction methods of grind noise are presented.
Technical Paper
2014-09-28
Juan Carlos Martinez Laurent, Adrian Jordan, Francisco Canales
Abstract The brake system and components are essential active safety systems for users of motor vehicles, one common NVH phenomenon known as Brake Disc Thermal Coning creates a perception of poor braking system performance. Although Brake Disc Thermal Coning does not deteriorate the braking distance or the vehicle performance, is a concern for the customer who identifies any undesired vibration as a potential performance loss resulting in complaints and warranty claims. In order to increase the quality, and reliability of the products, Automotive OEMs have created processes and tests, today incorporating the ones based in computational solutions, to identify, prevent and correct potential issues before its present in the final product. As computer technologies like Computer Aided Design (CAD), Computer Aided Engineering (CAE) and Computer Aided Manufacturing (CAM) have become more robust, and PC power clusters have increased the complexity of the problems resolution and decreasing the solver processing time, OEMs are moving forward from the road, to the lab and today to CAE.
Technical Paper
2014-09-28
Meechai Sriwiboon, Nipon Tiempan, Kritsana Kaewlob, Seong Kwan Rhee
The influence of processing conditions on Low-Copper NAO disc pads were investigated as part of an effort to develop Low-Copper disc pad formulations as this kind of information is not readily available in open literature. Processing conditions as well as formulation modifications are found to influence friction, pad wear, disc wear and brake squeal. Low-Copper disc pads for pick-up trucks, equivalent to an OE pad, are developed. It is also found that brake squeal measured during the SAE J2522 (AK Master) Performance testing is related to the combined total wear rate of the disc plus the inner/outer pads or the disc wear rate alone, and that there is a threshold wear rate, above which brake squeal increases rapidly.
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