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Viewing 211 to 240 of 7797
2017-03-28
Technical Paper
2017-01-1145
Eric De Hesselle, Mark Grozde, Raymond Adamski, Thomas Rolewicz, Mark Erazo
Abstract Hybrid electric vehicles are continuously challenged to meet cross attribute performance while minimizing energy usage and component cost in a very competitive automotive market. As electrified vehicles become more mainstream in the marketplace, hybrid customers are expecting more attribute refinement in combination with the enhanced fuel economy benefits. Minimizing fuel consumption, which tends to drive hybrid powertrain engines to operate under lugging type calibrations, traditionally challenge noise, vibration, and harshness (NVH) metrics. Balancing the design space to satisfy the cost metrics, energy efficiency, noise and vibration & drivability under the hybrid engine lugging conditions can be optimized through the use of multiple CAE tools. This paper describes how achieving NVH metrics can put undesirable boundaries on Powertrain Operation which could affect other performance attributes.
2017-03-28
Technical Paper
2017-01-1136
Jack S.P. Liu, Natalie Remisoski, Javed Iqbal, Robert Egenolf
Automotive vehicles equipped with Cardan joints may experience low frequency vehicle launch shudder vibration (5-30Hz) and high frequency driveline moan vibration (80-200Hz) under working angles and speeds. The Cardan joint introduces a 2nd order driveshaft speed variation and a 4th order joint articulation torque (JAT) causing the vehicle shudder and moan NVH issues. Research on the Cardan joint induced low frequency vehicle shudder using a Multi-Body System (MBS) method has been attempted. A comprehensive MBS method to predict Cardan joint induced high frequency driveline moan vibration is yet to be developed. This paper presents a hybrid MBS and Finite Element Analysis (FEA) approach to predict Cardan joint induced high frequency driveshaft moan vibration. The CAE method considers the elastically coupled driveshaft bending and engine block vibration due to Cardan joint excitation.
2017-03-28
Technical Paper
2017-01-1023
Yaqun Jiang, C. Hsieh, Georg Festag, Masood Ahmed, William Jiang
Abstract Large axial displacement at the edge of a flywheel causes a clutch to fail to disengage in high-speed rotation. To find out the root cause, a numerical procedure is proposed to investigate the vibration source and to understand dynamic behavior of the crank-train system. A simulation of the whole engine system including block, crankshaft, piston, and connecting rod was performed with AVL/Excite. The resulting CAE baseline model had good correlation with measurements. A comprehensive study was conducted for a set of flywheel and crankshaft models with different materials and unbalanced masses. The contribution to flywheel wobbling of each vibration order was carefully investigated, and an optimal design was presented.
2017-03-28
Technical Paper
2017-01-1064
Mustafa Yıldırım
Abstract Engine design is crucial in terms of NVH. It is the sources of vibration for a vehicle. Nowadays engine tends to being smaller and less stiff and more powerful according to predecessor. Small engines with high power is inherently generates extreme force and vibrations and accordingly generates more noise. Thus engine structure and also engine main components should be designed to prevent this vibration. There are two main sources: One of them is combustion and other is inertia loads. Due to this sources engine structure can cause severe vibration and accordingly this can cause noise via transmitting it into vehicle with both structure and airborne. This paper focused on to reduce engine vibration level with changing the combustion inputs such as cylinder pressure parameters and inertia parameters like piston mass, conrod length and balancing parameters. Design of experiment is used to obtain most robust case in terms of NVH.
2017-03-28
Technical Paper
2017-01-1070
Da Shao, Xu Sichuan, Aimin Du
Abstract The electromagnetic valve actuator (EMVA) is considered a technological solution for decoupling between crankshaft and camshaft to improve engine performance, emissions, and fuel efficiency. Conventional EMVA consists of two electromagnets, an armature, and two springs has been proved to have the drawbacks of fixed lift, impact noise, complex control method and large power consumption. This paper proposes a new type of EMVA that uses voice coil motor (VCM) as electromagnetic valve actuator. This new camless valvetrain (VEMA) is characterized by simple structure, flexible controllable and low actuating power. VCM provides an almost flat force versus stroke curve that is very useful for high precision trajectory control to achieve soft landing within simple control algorithm.
2017-03-14
Journal Article
2017-01-9277
Stefano D'Ambrosio, Alessandro Ferrari
Abstract The present paper illustrates an investigation about the potentialities of injection rate shaping coupled with an after injection. A pilot shot can either be absent or present before the rate-shaped boot injection. The experimental tests have been performed on a partial PCCI Euro 5 diesel engine endowed with direct-acting piezoelectric injectors. Starting from optimized triple pilot-main-after injection strategies, boot injection was implemented by maintaining the direct-acting piezo injector needle open at part lift. The results of two steady state working conditions have been presented in terms of engine-out emissions, combustion noise and brake specific fuel consumption. In addition, in-cylinder analyses of the pressure, heat-release rate, temperature and emissions have been evaluated. Considering the in-cylinder pressure traces and the heat release rate curves, the injection rate shaping proved to influence combustion in the absence of a pilot injection to a great extent.
2017-03-14
Journal Article
2017-01-9677
Chengwu Duan, Jian Yao, Ying Huang
Abstract A toothed chain continuously variable transmission concept is studied. By designing positive engagement at top overdrive ratio, we explored the potential to improve CVT mechanical efficiency. The low cost solution could improve fuel economy by 0.7% in FTP composite cycle. Preliminary multi-body dynamic simulation is also completed using VL-Motion to concept-proof the technical feasibility of disengagement and engagement. To address the noise issue resulted from abandoning the random pitch design in production chain, we proposed an alternate chain pitch sequence but more experimental data is required to validate the design.
2017-01-10
Technical Paper
2017-26-0270
Rahul Gurav, Kishor D Udawant, Ramkumar Rajamanickam, N V Karanth, S R Marathe
Abstract With emission norms getting more and more stringent, the trend is shifting towards electric and hybrid vehicles. Electric motor replaces engine as the prime mover in these vehicles. Though these vehicles are quieter compared to their engine counterpart, they exhibit certain annoying sound quality perception. There is no standard methodology to predict the noise levels of these motors. Electric motor noise comprises of mainly three sources viz., Aerodynamic, Electromagnetic and Mechanical. A methodology has been developed to predict two major noise sources of electric motor out of the three above viz. Mechanical and Aerodynamic noise. These two noise sources are responsible for the tonal noise in an electric motor. Aerodynamic noise arises most often around the fan, or in the vicinity of the machine that behaves like a fan. This noise is predominant at higher motor speed and also in electric vehicle due to higher speed fluctuation.
2017-01-10
Technical Paper
2017-26-0327
Onkar Deshpande, Shrikant Rangire
Abstract Increase in customer awareness for better vehicle noise together with strict pass-by noise limits have compelled the automotive industry to improve the overall vehicle noise performance. Out of various contributors to the overall vehicle noise, tail pipe noise is the major contributor. There is a need of efficient tail pipe noise measurement process for tuning the exhaust system. Modified methodology was proposed as conventional methodologies have limitations considering Indian scenario. In modified methodology tail pipe noise is measured during pass by noise test. This paper describes the comparative study of both methodologies with measurement results. Advantages and disadvantages of both measurement methodologies are also discussed.
2017-01-10
Technical Paper
2017-26-0183
Kedar Tare, Uttiya Mukherjee, Rohit J Vaidya
Abstract An automotive radiator cooling fan has been observed to be an important noise source in a vehicle and with increasing noise refinements, the need for a quieter but effective fan is of utmost importance. Although some empirical prediction techniques are present in literature, they are not sufficiently accurate and cannot give a detailed view of the entire noise spectrum and the various noise prone zones. Hence the need for highly accurate Computational Fluid Dynamics (CFD) study is essential to be able to resolve the minute acoustic stress. Large Eddy Simulation technique in CFD is used to resolve the minute scales of motion in the flow as the sound pressures simulated are very small compared to system level pressures and require immense accuracy. Detailed mesh dependency and Y+ studies are conducted to implement higher accuracy as well as keep mesh requirements within computationally feasible zone.
2017-01-10
Technical Paper
2017-26-0188
Prasad Yadav, Harshal Bankar, Nagesh Voderahobli Karanth
Abstract Diesel powered electric generators are used in a variety of applications, such as emergency back-up power, temporary primary power at industrial facilities, etc. As regulatory and customer requirements demand quieter designs, special attention is given to the design of acoustic enclosures to balance the need of noise control with other performance criteria like ventilation and physical protection. In the present work, Statistical Energy Analysis (SEA) approach augmented by experimental inputs is used to carry out Vibro-acoustic analysis of an enclosure for higher capacity Diesel generator set. The exterior sound radiated from an enclosed generator is predicted and further enclosure is optimized for an improved sound-suppression. The airborne sources such as engine, alternator, radiator fan and exhaust are modelled explicitly using experimental noise source characterization. Structure borne inputs are also captured in the test for improving modelling accuracy.
2017-01-10
Technical Paper
2017-26-0189
Keshav Mutalik, Atul A Gaikwad, Nagesh Voderahobli Karanth, Shriniwas Chivate
Abstract The parameters such as lower noise levels, quietness, etc. of a vehicle has no longer remained the only driving features since the passenger car buyers are greatly influenced by the perception of the sound. In a scenario like this, the sound quality becomes of great importance especially for smaller diesel powertrains as they are more annoying than their gasoline counterparts. The idling noise is critical as its noise creates the first impression of the vehicle on the buyer. The Indian passenger car market is dominated by diesel cars equipped with smaller engines less than 2 liter capacity. Present work describes the methodology to formulate the equation for annoyance/pleasantness for the diesel powertrains used in Indian passenger cars. The index, Sound Annoyance Rating (SAR) developed through this work is significant for powertrain level target setting and benchmarking purposes.
2017-01-10
Journal Article
2017-26-0190
M L Munjal, Vikas Kumar
Abstract High insertion loss is desirable and can be achieved by using plug-muffler elements which consist of two cross-flow perforated sections. However, the plug-mufflers have an inherent disadvantage of high back-pressure which may affect the engine performance adversely. In this paper, a novel structural modifications has been introduced to the plug-muffler to obtain better acoustic performance as well as low back-pressure. Three configurations have been analyzed here including the classical plug-muffler configuration. Back-pressure has been calculated using the lumped flow-resistance network theory for all three configurations and compared. To evaluate the transmission loss, the 1-D (plane wave) analysis has been carried out using the Integrated Transfer Matrix (ITM) method and the results so obtained are validated against 3-D FEM using a commercial software.
2017-01-10
Technical Paper
2017-26-0191
Mayur Birari, Arvind Yadav, Vilas Bijwe, Dayanand Billade
Abstract As automotive technology has evolved, gear rattle has become a prominent contributor for cabin noise as the masking from the engine noise has decreased. The market and customer expectation make the rattle noise a question to be addressed as early as possible in the vehicle development process. However, to simulate rattle, it calls for a detailed modeling of different complex subsystems of driveline to represent their true characteristics. Thus, the paper adopts an FE based elastic multi body dynamics model to predict gear rattle. The approach involves modeling of a complete flexible driveline using condensed FE models from Nastran in AVL Excite Powerunit/Transmission module. It includes combustion pressure as input excitations to crankshaft and then predicts parameters like gear teeth impacts, gear normal meshing force, dynamic mesh stiffness & overall contact state in transient and frequency domain. The output parameters are then analyzed to evaluate the rattle index.
2017-01-10
Technical Paper
2017-26-0194
Ramkumar Rajamanickam, Shriniwas Chivate, Gaurav Shinde, Nagesh Voderahobli Karanth, Shalil Akre, Kishor Desale
Abstract Sound Quality (SQ) of brake and clutch pedal assembly plays an important role in contributing to vehicle interior noise and perception of sound. Quiet operation of brake and clutch units also reflects the vehicle built and material quality. Noise emitted from these sub-assemblies has to meet certain acceptance criteria as per different OEM requirements. Not much work has been carried on this over the years to characterize and quantify the same. An attempt has been made in this paper to study the sound quality of brake and clutch pedal assemblies at component level and validate the same by identifying the parameters affecting SQ. Effect on noise at different environmental conditions was studied with typical operating cycles in a hemi-anechoic chamber. The effect of sensor switches integrated within the clutch and brake pedal on sound quality is analyzed. It is found that the operating characteristics of switches drives the noise and SQ.
2017-01-10
Journal Article
2017-26-0205
Milind Ambardekar, Nayankumar Solanki
Abstract Before a physical proto-vehicle is assembled, various components or subsystems are ready by Tier-I or II suppliers. During final design judgement of the vehicle thru’ CAE or Mule-vehicle testing, performance target compliance need be assured for all these components to meet the Vehicle-level NVH targets. The work here studies some of the major components of a passenger car. Their individual NVH response can be critical to be cascaded for meeting the final targets for the vehicles running over roads. Conclusions of the study challenge some of traditional beliefs or generic targets. Often the component level response deviating from its own targets may not have an adverse influence on NVH of the vehicle facing multiple excitations from tyre/road, wind and power-train in a frequency band of interest.
2017-01-10
Technical Paper
2017-26-0198
Chandrakant Parmar, Sashikant Tiwari, Apoorv Chauhan, Shourya Srivastava, Sarvanu Gangopadhyay
Abstract The present work focuses on optimization of gear shift pattern of an AMT vehicle to improve its NVH performance without causing any adverse effect on any other vehicle performance attribute. The vehicle which was identified with the structural body resonance at low frequency had discomforting boom noise in a particular engine rpm zone and at corresponding vehicle speed. With the initial shift pattern (will be referred as V1 gear shift schedule), the gear shifts were calibrated such that when vehicle is driven in the city with 20 to 60 kmph speed, the vehicle operated mostly in the best fuel economy zone but it used to pass through structural resonance frequency. This resulted in the presence of continuous boom leading to an unpleasant driving experience. In order to avoid the presence of boom noise during city driving, the gear shift points were optimized (will be referred as V2 gear shift schedule) such that the vehicle did not operate in affected engine speed range.
2017-01-10
Technical Paper
2017-26-0196
Kopal Agarwal, Sandip Hazra, Vikas Kolage
Abstract Key on/off Vibrations plays an important role in the quality of NVH on a vehicle. Hence having a good KOKO in the vehicle is desirable by every OEM. The vibration transfer to the vehicle can be refined by either reducing the source vibrations or improving isolation. In this study, critical factors affecting KOKO vibration has been identified. Focus has been given on improving the KOKO by change in mounting system stiffness & stopper gap, and assuming other parameters as constant. The study highlights a new simulation approach using ADAMS View to help run a DOE for solving KOKO issue on vehicle. The contribution of C mount stiffness and stopper gap is shown through simulation results. The correlation between simulation & test results has been established by measuring rigid body modes and KOKO vibration on vehicle for a set of mount configuration. Test results show significant KOKO improvement with the mount configuration optimized through simulation.
2017-01-10
Technical Paper
2017-26-0195
Sachin Kumar Jain, Manasi Joshi, Harshal Bankar, Prashant Kamble, Prasad Yadav, Nagesh Karanth
Abstract The paper discusses the methodology for measuring the sound absorption of sound package materials in a different sizes of reverberation chambers. The large reverberation chamber is based on test methods and requirements as per ASTM C423 and ISO 354 standards. Both the test standards are similar and recommend a reverberation chamber volume of at least 125 m3 and 200 m3 respectively for sound absorption measurements from 100 Hz to 5000 Hz. The test sample size requirements are from 5.5 to 6.7 m2 as per ASTM C423 and 10 to 12 m2 as per ISO 354. In the automotive sector passenger car, heavy truck, and commercial vehicle, the parts that are used are much smaller in size than the size prescribed in both the standards. The requirement is to study the critical parameters such as the chamber volume, sample size, reverberation time and cut-off frequency etc. which are affecting the sound absorption property of acoustic material.
2017-01-10
Technical Paper
2017-26-0210
Surinder Kumar, Harveen Talwar
Abstract With the development of automobile industry, customer awareness about NVH (Noise, Vibration and Harshness) levels in passenger vehicles and demands for improving the riding comfort has increased. This has prompted automobile OEMs to address these parameters in design stage by investing resources in NVH research and development for all components. Better NVH of Radiator Fan Module (RFM) is one of the parameters which contributes to cabin comfort. The basic objective of RFM is to meet engine heat rejection requirements with optimized heat transfer and air flow while maintaining NVH within acceptable levels. The rotating fan (generally driven by an electric motor), if not balanced properly, can be a major source of vibration in the RFM. The vibration generated thus, can be felt by customer through the vehicle body.
2017-01-10
Technical Paper
2017-26-0209
Gaurav Jeevanrao Shinde, Ramkumar Rajamanickam, Nagesh Voderahobli Karanth, D W Pande
Abstract With growing demand of comfort of cars, number of small electric motors used for adjustment of different functional units is steadily increasing. Due to the various rotational components and the forces they accord, electric motors radiate significant amount of noise at high frequencies with tonal components that can be annoying. Motor noise comprises three sources namely: electromagnetic, aerodynamic and mechanical. This study considers mechanical and electromagnetic sources of Electric Power Assisted Steering (EPAS) motor used in passenger cars. This paper describes an approach to assess noise and vibration parameters between field motors and fresh motors. Noise and vibration spectrums are analyzed in terms of frequency contents and dominancy of mechanical sources in sound power radiated by motor is discussed. FE modal analysis of motor is performed and correlated with impact hammer measurements to quantify structure borne energy contribution.
2017-01-10
Technical Paper
2017-26-0207
Dayal Mirthinti, Dinesh Sahrawat, Rohit Dang
Abstract In automobile, NVH has been playing an important role in defining the overall quality of the vehicle. Continuous efforts are being put in globally by engineers to make the travel experience as comfortable as possible for both commercial and passenger segment vehicles. The front wiping system being a critical safety feature in an automobile is one of the sources of structural vibrations/noise due to numerous moving child parts. Therefore, the layout of the wiper motor in the vehicle is an important aspect of Vehicle NVH. These vibrations and noise levels become more pronounced if the wiper motor is mounted inside the passenger compartment, a layout that is commonly seen in commercial vehicles. This paper focuses on measures to improve the NVH while having the layout of the wiping system inside the passenger compartment of the vehicle.
2017-01-10
Technical Paper
2017-26-0206
Muthukumar Arunachalam, Sankarasubramanian Thirukkotti, S Arunkumar, Abdul Haiyum
Abstract Modern day customer awareness on noise and comfort is extremely increasing, which demands OEM manufacturers to focus on NVH attributes and to meet environmental legislative requirements. Noise generation mechanism in Air Intake System (AIS) is one of the major sources for vehicle interior noise and it occurs mainly because of air column oscillation by sharp pressure pulsation from opening and closing of valves in engine cylinders. Air intake system designer has immense challenges to attenuate intake noise during design stage, in order to meet the vehicle interior noise requirements by using multiple resonators to tune the desired broad band frequencies and to choose the optimum number of resonators. The placement of resonator on both the clean duct and dirty sides is also a key challenge for better noise reduction from air intake system.
2017-01-10
Technical Paper
2017-26-0217
Arvind Kumar Yadav, Mayur Birari, Vilas Bijwe, Dayanand Billade
Abstract Crank train torsional vibration is an important aspect for design and development of Powertrain for NVH refinement and durability. Crank train torsional vibration parameters like angular acceleration of flywheel or twist, depends upon various design parameters like geometry of crankshaft, mass of flywheel, stiffness of clutch, mass of pulley etc. It also depends upon engine operating conditions like engine speed, engine load, combustion peak pressure and combustion pressure variation etc. Most of these parameters are decided by engine power, torque, engine architecture and packaging constraints. Addition of torsional vibration damper (TVD), which works on the principle of tuned dynamic absorber, is commonly deployed design solution to control the torsional vibrations as well as stresses (to improve durability of crank train) induced in crank train assembly at specified modal frequency.
2017-01-10
Technical Paper
2017-26-0215
Kodali Ajay Krishna, Sanjeev Patil
Abstract In today's competitive automobile marketplace with reduced vehicle development time and fewer prototypes/tests, CAE is playing very crucial role in vehicle development. Automobile environment demands ever improving levels of vehicle refinement. Performance and refinement are the key factors which can influence the market acceptance of vehicle. Driveline is one of the key systems whose refinement plays critical role in improved customer satisfaction. Because of the virtue of the driveline functionality, driveline induced noise and vibration are the most common issues in the AWD vehicle development programs. Refinement of the drive line needs complicated nonlinear full vehicle CAE MBD models for the evaluation of driveline induced noise and vibration responses at different operating conditions [1]. In this paper a simplified approach is adapted for solving the Noise & Vibration issue which has been identified at the prototype testing level of an AWD vehicle development.
2017-01-10
Technical Paper
2017-26-0213
Michael Thivant, Pascal Bouvet
Abstract In the context of the upcoming reduction of Pass-By-Noise limits in the EU regulations, automotive manufacturers need to implement new concepts of shielding package. ECOBEX is a French funded research project aiming at reducing the powertrain noise contribution of the vehicle, whilst restricting additional mass and cost. Bringing together OEM, raw materials suppliers, shielding manufacturers, universities and specialized consultants in this research program enabled innovations in materials, design, tests and computational methods. This paper will focus on a new procedure for the optimization of the shielding package, based on a precise 3D localization and quantification of the acoustic sources of the powertrain and on their implementation in an Energy Boundary Element model, computing the acoustic propagation. Intensity maps emphasized the dominant acoustic paths and highlighted mitigation opportunities in terms of absorption and insulation.
2017-01-10
Technical Paper
2017-26-0221
Swamy Mukkera, Aditya Pandey, Kodali Ajay Krishna, Sanjeev Patil, P L N Prasad
Abstract Wind noise is becoming important for automotive development due to significant reductions in road and engine noise. This aerodynamic noise is dominant at highway speeds and contributes towards higher frequency noise (>250Hz). In automotive industry accurate prediction and control of noise sources results in improved customer satisfaction. The aerodynamic noise prediction and vehicle component design optimization is generally executed through very expensive wind tunnel testing. Even with the recent advances in the computational power, predicting the flow induced noise sources is still a challenging and computationally expensive problem. A typical case of fluid-solid interaction at higher speeds results into broadband noise and it is inherently an unsteady phenomenon. To capture such a broad range of frequency, Detached Eddy Simulation (DES) has been proven to be the most practical and fairly accurate technique as sighted in literature.
2017-01-10
Technical Paper
2017-26-0211
Shriram K. Kulkarni, B Venkatakiran, Omprakash Sahu, Vilas Bijwe, Manoj Joshi, Dhanaji Kalsule
Abstract Today’s competitive market demands for low cost passenger cars with lighter, smaller size, peppy response and fuel efficient engines and having world class NVH refinement levels. For such requirements, it is essential to optimize the product starting from the design conceptual stage, considering all performance aspects. Generally, three cylinder engines, due to less reciprocating masses, compared to four-cylinder engine, are said to be fuel efficient for the same capacity. Nevertheless, NVH problems caused by inherent imbalance forces and couples remain as drawback of the three-cylinder engine. However, through optimal design of the crank train, control of cylinder to cylinder pressure variation, stiffening of the engine structure, optimizing the integration with a vehicle through proper design of mounts, NVH refinement levels can be improved.
2017-01-10
Technical Paper
2017-26-0220
Ashutosh Dubey, Palish Raja, Nitin Chopra, Ashok Patidar, Manu Kaushik
Abstract With the increase in the sensitivity of power steering system in the competitive environment, it becomes essential to provide a trouble free steering system to the customer. Usually major concerns faced in the performance of steering system are related to noise like vane pump whining noise and steering gearbox erratic rubbing noise. Even though selected steering pump and reservoir are quite compatible to the steering gearbox. With the series of Computational Fluid Dynamics (CFD) simulations and field tests, it is found that the cavitation phenomena in steering oil routing lines is responsible for the steering turning noise. In this paper, a developed systematic approach for problem detection to implementation of design solution is discussed.
2017-01-10
Technical Paper
2017-26-0219
S Nataraja Moorthy, Manchi Rao, Prasath Raghavendran
Abstract Globally the customers are demanding more powerful yet silent vehicles to enhance their daily commuting and goods transportation needs. The current trend in the design is to enhance the engine power without major change in the physical configurations of the engine systems. Increasing the power and torque of the powertrain will have an undesirable and adverse effect on NVH levels. In this research work, a light weight rear wheel drive vehicle was investigated from torsional vibration perspective. The vehicle is powered by a two cylinder engine with turbo charger. The power and torque of the vehicle was increased approximately two times with the help of turbocharger which resulted in increasing the powertrain torsional vibration. This increased vibration was further amplified through inevitable driveline resonances which causes severe vibration at the passenger seat location and steering. Also, the noise levels are above the comfortable zone.
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