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Technical Paper
2013-11-27
Bharani Dharan R, Raghu Ram Goud, Rajkamal manoharan, Vikas Dhiman
Engine Block, being the most vital component requires serving various functions all together. Design of block for higher power densities and BMEP levels, needs a complete change in the design strategy compared to the existing design approach. Also, balancing other factors like engine cooling efficiency, blow by targets, weight, and manufacturing cost becomes a huge challenge upfront in designing an engine block. Design of block is carried out within several design, assembly and manufacturing constraints such as to maintain a specific cylinder centre distance, Block NVH, Better cooling jacket, controlled bore deformation and incorporation of various accessories viz. CRDI System, Fuel Filter, Oil Filters, Fuel Injection System, steering pump, Air Compressor etc. This paper portrays the complete perspective and design methodology used during design process. Integration of classical methods, and FE analysis is presented. FE analysis is mainly carried out for understanding bore deformation, stress flow path and cylinder head gasket pressure distribution.
Technical Paper
2013-11-27
Arpan Nagar, Venkatesan Chokkalingam, Nithiyanandam Umashankar, S Ravi Shankar
The crankshaft twist is of great concern for heavy duty engines. In order to have a longer B10 life and better NVH characteristics, it is desired to have minimum Torsional vibrations (TV) in the crank shaft. To keep the crankshaft twist in check - TV dampers are used. Aneasier approach is to use a Viscous TV damper which keeps TV below acceptable limit for entire speed range. But this is a very costly approach. In this paper, the design of rubber TV damper for multi-cylinder engine was optimized to have lower TV characteristics. The optimized rubber damper has been developed with AEM - VAMAC™ grade rubber. This material provides advantages of better TV attenuation, higher thermal resistance, oil resistance higher durability and a much longer life than other rubber compositions. Besides rubber profile was also optimized to obtain higher slip torque. The TV amplitudes with existing rubber compound (EPDM -Ethylene Propylene Diene Monomer) were measured in the engine testbed. The optimized TV damper with AEM - VAMAC™ rubber compound clearly indicates a reduction of about 50% in TV amplitudes for the critical orders of a multi-cylinder diesel engine.
Technical Paper
2013-11-27
Ankit Pant, Chetan Prakash Jain, Deepak Kumar Panda
For any new vehicle development, NVH target setting is crucial activity. Structural modification are to be done in early design phase to improve cabin comfort by identifying the sensitive paths and taking appropriate countermeasures for reduction of noise or vibrations transmission to cabin. A benchmark vehicle is taken to define the target areas for next model development. Numerical computations with suitably modified virtual model are carried out to accelerate the development cycle. Transfer path analysis (TPA) is an established technique for estimation and ranking of individual low-frequency noise or vibration contributions via the different structural transmission paths from point coupled powertrain or wheel-suspensions to the vehicle body [1]. TPA technique can also be used to define the improvement targets for future vehicles. This paper presents the methodology of carrying out the “Target Setting” using TPA for numerical model development for new model prior actual prototyping which will result into achieving desired NVH level in cabin.
Technical Paper
2013-11-27
Prasad M. Rao
The paper concentrates on generating maximum tire grip by using the frequency response system of individual automobile components. Tire data has been consulted for and used to verify the findings presented in this paper. The tire data has been provided by the FSAE Tire Test Consortium (TTC) & Calspan Tire Research Facility (TIRF), U.S.A. specifically for FSAE/FS teams. Tire parameters such as vertical load, tire temperature, tire pressure, etc. have been given highest weightage as they directly affect the major force outputs in addition to frequency excitement. Suspension geometry design and its role as a precursor to an effective shock absorbing setup have been highlighted here. The damping has been calculated and algorithms related to it have been presented here since effective and quick response of the vehicle's behaviour can be modified through this. Frequency algorithms have been generated after crosschecking with tire data that aim at maximizing tire grip. The base automobile used here is a Formula Student vehicle built as per the 2011 rules and regulations.
Technical Paper
2013-11-27
Ninad Pimpalkhare, Gaurav Gupta, Mugundaram Ravindran, Chetan Prakash Jain, Chiranjit Ghosh, Prince Shital
Structure borne noise is the major source of noise inside the vehicle compartment. Recently the quietness of the occupant cabin has become an important dimension to the quality of product. OEMs are finding it challenging to meet the customer expectations for “Powerful yet quiet” attribute. Several focused studies have been made to reduce the under hood component noise in automobiles. This paper summarizes the optimization of vibro-accoustic sensitivity (VAS) of the engine mounts in passenger car engine. The contribution of each engine mount on the structure-borne noise transfer inside the cabin is studied by conventional FRF and normal mode analysis using Nastran, along with physical testing validation. This paper emphasizes to reduce the structure borne noise with the focus on weight reduction of the body side engine mount.
Technical Paper
2013-11-27
Chandra Sekhar J, Ramkumar Rajamanickam, E Ramachandran, Nagesh Voderahobli Karanth
Modal analysis is a specialized tool which has been used for many years to reliably estimate various parameters such as natural frequency, mode shape and damping. Since these parameters have direct relevance to the behavior of any component or structure and the resultant vibrations, the methods used for evaluation of these have been taken up as a part of this project. MATLAB is a platform that serves analysis purpose and offers many advantages over dedicated, menu driven systems. Open function assure flexibility and possibility to modify functions for specific needs and also providing traceability and quality assurance. The current paper targets to make a comparative evaluation of various modal parameter estimators using existing MATLAB tools for determining modal parameters for simple structures. FRF measurements on simple structures are carried out and the data is processed using MATLAB run parameter estimators. The computed results are compared and advantages and limitations of the estimators are discussed.
Technical Paper
2013-11-27
Kalyan S. Hatti, Vijay Antony John Britto, Sai sankaranarayana
In the automotive industry several attributes needs to be considered for the development of a new vehicle which are important for the customer, such as vehicle dynamics, driveability, fuel consumption, emissions, durability and NVH among many others. Sometimes these characteristics are conflicting and often need is to create a robust trade-off where the design space is sufficient to fit all of them in a vehicle that rhymes with the brand image and is appealing to the intended customer. Automobile manufacturers try to meet the requirements with respect to quality and comfort and often, emotional, aspects supercede the previous objective, pragmatic demands. The satisfaction of the demands by the customers concerning comfort, driving pleasure, design appears dominant and functionality criteria sometimes takes a back seat. NVH is considered to be one of the key buy in factor among the above mentioned attributes. This paper discusses on how the NVH aspect plays an vital role to get a competitive advantage over other vehicle aspects Moving from traditional approach of - ‘Test -Analyse -Fix’ to ‘Design Right First Time’ has been experienced.
Technical Paper
2013-11-27
Aditya Palsule, Nagasuresh Inavolu, M Jaganmohan Rao, Kalyan Hatti
The present work focusses on the Noise &Vibration refinement carried out on a Heavy commercial vehicle (HCV). In a heavy commercial 4×4 vehicle the existence of an auxiliary gearbox (AGB) is primarily for switching between the multiple drive options. The AGB can become an additional source of noise from the drive train. In this particular vehicle the overall noise from the vehicle has particularly been dominated by the noise from the AGB in specific drive options and conditions as experienced during the subjective assessment of the vehicle initially. First assessment was made by modifying the gear tooth geometry and then the gears were changed from spur to helical as a part of the AGB refinement process. The results of both these assessments were compared. A considerable improvement in the AGB noise was thereby achieved.
Technical Paper
2013-11-27
Kishore Chittilla, Yogesh Yeola, Ashish Tiwari, Ramkumar Rajamanickam
Tire modal performance plays an important role in passenger car NVH refinement which includes road induced noise. Work done in the past, enumerates testing methods, excitation technique applied and boundary conditions. It also includes Mode shapes, analysis results and study of variables affecting the modal performance of passenger car Tire. Here, in this paper an attempt is made to compare the experimental modal analysis results, obtained using two different excitation techniques for exciting tire. In the experimental modal analysis under discussion, the passenger car tire of type 175/65R14, was inflated up to 2.2 bar (32psi) pressure in free-free condition. Impact Hammer and Electro-dynamic shaker were used to excite the tire structure in radial direction. Single Input Multiple Output technique was used for excitation and response signal acquisition. Modal parameters of the tested tire were identified in the frequency domain with curve fitting technique and modal parameter estimation technique.
Technical Paper
2013-11-27
Shantanu Rohidas Tathe, Kiran P Wani
Whole body vibration deals with the biodynamic responses of human body in various postures. Vertical vibration exposure in sitting posture is common situation encountered while driving vehicle or riding motorcycle. We have chosen Wan & Schimmel's 4 DOF biodynamic model for this study by referring the goodness of fit results for various models available in the literature. A single degree of freedom model of motorcycle is used for analysis of whole body vibration on two wheeler. We have neglected pitch, yaw movements of two wheeler for purpose of simplicity. Whole body vibration analysis for human body in sitting posture is described by three terms i.e. Seat to Head Transmissibility (STH), Driving point impendence (DPM) & apparent mass (AP). In order to analyze human response on motorcycle Road to head (RTH), Road to lower torso (RTLT), Road to viscera (RTV), Road to upper torso (RTUT) responses are calculated for different motorcycle suspension natural frequencies. Simulation of biodynamic model is carried in MATLAB which shows close match with experimental results from literature.
Technical Paper
2013-11-27
Chatterjee Joydeep, Chetan Prakash Jain, Deepak Kumar Panda
Road/Tire noise is an important product quality criterion for passenger cars which are driving customers to decide upon the selection of a vehicle. Reduced engine noise and improvement in road conditions has resulted into more road/tire noise problem as average vehicle speed has gone up. Excitations from road surface travelling through the tire/suspension to vehicle body (structure-borne path) and air-pumping noise caused by tread patterns (air-borne paths) are the main contributor to tire noise issue inside the vehicle cabin [1]. A lot of emphasis is put on the component level design as well as its compliance with vehicle structure to reduce the cabin noise. The objective of this work is to establish a methodology for evaluating structure-borne road/tire noise by evaluating the tire structural behavior and its interface with the vehicle body and its suspension system and identifying the contributing critical paths. NVH techniques like Modal Parameter Estimation and Transfer Path Analysis are used to characterize the contribution of noise from tires.
Technical Paper
2013-11-27
Ammar Ali, Aditya S. Luktuke, E. Ramachandran, N.V. Karanth
Greater customer awareness is driving the automotive industry to constantly look to innovate and ensure that greater time, efforts and considerable resources are spent in developing a better vehicle. As we move away from noisy vehicles, the differentiating parameter in vehicles is the perception of quality in the vehicle noise or sound. As the masking effect due to overall vehicle noise level abates, many low noise sources gain prominence, which directly influences the perception of noise refinement. Hence, the concept of vehicle interior noise is not only limited to lower noise levels but has also extended to better sound quality (SQ). SQ technique involves use of relevant parameters for quantifying a subjective quality into an objective quantity. This paper will look at parameters relevant to subjective perception of vehicle interior noise and consider a benchmarking methodology targeting vehicle sound quality. A few vehicle test conditions relevant for vehicle SQ perception were identified.
Technical Paper
2013-11-27
Marco Mammetti, Juan Garcia, Marina Roche Arroyos
Reduction of CO2 emission is a mandatory objective for every actor in the field of automotive transport, and electric vehicles (EV's) are increasingly becoming an effective option for both OEMs and customers. However, components development and vehicle integration for EV's present new challenges that must be faced and new issues which need to be solved. In particular electric motor control systems are developed to achieve the same comfort conditions as in conventional vehicles. IDIADA developed a prototype electric commercial vehicle in which both the motor and driveline were integrated. The electric motor output shaft delivers the torque to the transmission under a certain level of load variation and with torque irregularities that must be smoothed out in the transmission components. This paper studies the results of the testing of the prototype vehicle carried out to improve the overall NVH behavior of the powertrain. The test results revealed that abrupt change in frequency content must be limited in order to avoid torque irregularities from the motor to the transmission.
Technical Paper
2013-11-27
Sivapriya Balasubramanian, Santosh Gosavi
Vehicle floor vibration is the resultant of different road inputs damped through various transfer paths. Seat comfort, which depends on these floor vibrations, can be evaluated with a single input signal “Pink noise”; which constitutes various road inputs. Transmissibility of seat structure on a vibration shaker with pink noise input includes all possible responses of road inputs. Still, transmissibility profile at vehicle end and component level varies. This is due to the utilization of “dummy” on component level testing on vibration shaker, which acts as a dead weight with dissimilar damping characteristics of human. A transmissibility correlation between human and dummy is attained by replacing the dummy in place of human and actuating it to find the difference in contribution between them for different class of vehicles. This contribution extrapolation from the damping effects of human and dummy is applied on dummy transmissibility. This results in a complete solution for attaining real time vehicle level seat structure transmissibility at component level testing.
Article
2013-11-26
UniWest has expanded the EddyView family with three portable eddy current testing instruments: the Prime, Pro, and Premium instruments are off-the-shelf and readily available.
Article
2013-11-26
Asylum Research’s blueDrive photothermal excitation is available on its Cypher atomic force microscopes.
Article
2013-11-26
ARPA-e targets "robust" batteries that not only bear loads but also absorb crash-impact energy to save weight.
Article
2013-11-24
Researchers devised the tests to prove that active flow control can enhance the performance of a vertical tail enough to allow future designers to reduce the size of the structure for a whole family of airplanes.
Article
2013-11-22
Now that simulation and modeling are common techniques for designing equipment, standards groups are stepping in to add a bit more structure and compatibility for these tools. Two trade associations have paired up to establish a working group that aims to make it simpler to merge engineering analysis with overall systems behavior analysis.
Standard
2013-11-20
This test method is applicable for rating various materials, such as automotive trim materials and insulation composites, for their ability to resist heat transfer, heat degradation, odor, smoking, and exothermic reaction under prescribed temperature. 1.1 Purpose The purpose of this testing method is to obtain comparative data which can be used to evaluate heat resistance and thermal insulation properties of various materials or composites when subjected to time and temperature conditions which reflect “in-car” situations.
Technical Paper
2013-11-20
David Lennström, Roger Johnsson, Arne Nykänen, Anders Ågren
System and component target setting for noise and vibration are important activities within automotive product development. New challenges arise when electric motors are introduced into cars traditionally powered by combustion engines. The emitted noise from an electric traction motor for hybrid electric vehicles is characterized by high frequency tonal components from the dominating magnetic harmonics which can be perceived as annoying. Sound power is frequently used for quantifying the airborne noise from rotating electrical machines. This paper describes the process of determining the radiated sound power from an automobile electric rear axle drive in-situ and its contribution to interior cabin noise for a prominent rotor order. The sound power was calculated by combining the average stator surface vibration velocity together with an estimate of the radiation efficiency. To model the radiation efficiency, the vibration shape of the cylindrically shaped stator shell was determined by means of operational deflection shapes.
Technical Paper
2013-11-20
Roger Johnsson, Arne Nykänen
During the winter special winter tires are used to prevent the car from slipping and the grip can be improved by using studded tires. Studded tires are known to cause higher noise levels and noise that is perceived as more annoying than non-studded tires. The objective was to model the interaction between the stud pattern and the stud/tire response (i.e. sound) caused by the excitation of the studs, and to make the result audible. In this study the interior airborne noise caused by the studs was auralized using a combination of recordings, modeling and filtering. The proposed stud auralization model makes it possible to evaluate the influence of the stud pattern and the stud/tire response at any desired speed. The noise caused by the studs is determined by the stud/tire responses when studs hit the pavement, the stud pattern and the speed of the tire. The stud patterns and the stud/tire responses were measured for 5 different studded tires. Auralizations were created for all combinations of stud patterns and responses at two different speeds.
WIP Standard
2013-11-14
This SAE Standard establishes the test procedure, environment, and instrumentation for determining the exhaust sound pressure levels of motorcycles under stationary conditions. Since initial publication, it has been successfully applied to regulation and monitoring of sound pressure levels of off-highway vehicles, and that remains its recommended application. Users of SAE J1287 for the purpose of roadside enforcement of sound pressure levels for on-highway motorcycles have reported difficulties with its implementation in that application. In response, SAE J2825 was developed, and is recommended for measurement of exhaust sound pressure levels of stationary on-highway motorcycles. Care must be taken not to confuse stationary sound pressure levels with total motorcycle sound pressure levels. This test does not evaluate total motorcycle sound during operation. For this purpose, SAE J331 or SAE J47 is recommended. Any allowable sound limits (dBA) set in relation to SAE J1287 for exhaust sound pressure level should not conflict with the allowable sound limits (dBA) for total sound pressure level per the EPA requirements specified in the US Code of Federal Regulations, 40 Part 205.
Article
2013-11-13
A forum at the 2013 SEMA Show discussed three approaches to ensure performance parts compliance with federal safety standard No. 126. Panelists also explained how simulation data, and kinematics and compliance measurements, can improve performance parts design.
Article
2013-11-12
MESSRING offers the new M=BUS in-dummy data acquisition system for the WorldSID (Worldwide Harmonized Side Impact Dummy) 5th Small Female Dummy.
Standard
2013-11-07
This SAE Standard establishes the test procedure, environment, and instrumentation for determining the exterior sound level for passenger cars, multipurpose vehicles, and light trucks having a gross vehicle mass rating of 4540 kg or less. The test procedure is characterized by having fixed initial conditions, i.e., an as-specified initial vehicle speed and gear selection at a fixed start point on the test site. Full-throttle acceleration and closed-throttle deceleration of the vehicle are included in this procedure. Sound levels determined in accordance with this document are dependent on the performance capability of the test vehicle, as influenced by power-to-mass ratio and overall powertrain gear ratio.
Standard
2013-11-07
This SAE Standard is equivalent to ISO Standard 362 - 1997 except for the differences detailed in Appendix A, and includes the modifications adopted by WP 29 in ECE R51 Revision 1 and EEC 92/97 and EEC 96/20. This document specifies an engineering method for measuring the noise emitted by accelerating highway vehicles of all types (except motorcycles) in intermediate gears with full utilization of the available engine power. The method is designed to meet the requirements of simplicity and reproducibility of results under realistic vehicle operating conditions. Measurements relate to operating conditions of the vehicle which give the highest noise level consistent with urban driving and which lead to reproducible noise emissions. Therefore, an acceleration test at full throttle from a stated engine or vehicle speed is specified. The test method calls for an acoustical environment which can only be obtained in an extensive open space. Such conditions can usually be provided for: a. Measurements at the manufacturing stage b.
Article
2013-10-31
New R-1234yf production is promised by Arkema. SAE Cooperative Research Group shows R-445A blend has potential, and vehicle prototype charging equipment for assembly line and service shop is undergoing testing. German automakers resurrect the R-744 (carbon dioxide as a refrigerant) development program.
Article
2013-10-31
Combustion simulation has the potential to help engine manufacturers design better engines in less time with less cost.
Article
2013-10-30
In an attempt to achieve a balance between Reynolds number, model scale, and tunnel blockage issues, a 1:3 scale heavy-vehicle testing program has been initiated at the Monash University 1.4-MW wind tunnel.
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