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A Study on the Decay Process in the Time-Frequency-Dependent Combustion-Noise-Generation Model for Diesel Engines

Graduate School of Sciences and Technology for Innovation, Y-Hitoshi Oguchi, Masato Mikami
  • Technical Paper
  • 2019-32-0512
To be published on 2020-01-24 by Society of Automotive Engineers of Japan in Japan
We experimentally investigated the process of decay of engine noise from a single-cylinder diesel engine considering the time-frequency-dependent combustion-noise-generation model. In this model, the vibration energy of each frequency component is assumed to accumulate in the engine structure excited by the combustion impact during the combustion period in a cycle and decay over time, and the combustion noise is assumed to radiate from the engine surface. We used wavelet transform analysis as a time-frequency analysis of the sound pressure to obtain the decay rate, c, of the engine noise power. In order to investigate the dependence of the decay rate, c, on the sound-source location, we placed eight microphones in different positions near the engine. In order to investigate the dependence of the decay rate on the maximum in-cylinder pressure rise, we conducted experiments under three different operating conditions. The shape of the temporal variation of the engine-noise power depended on the sound-source location while the value of the engine noise power depended on the maximum in-cylinder pressure rise. Based on the time-frequency-dependent combustion-noise-generation model,…
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Brake noise analysis on tractive axle of 6x2 tractor vehicle

CNHI - Iveco Latin America / UFMG – Programa de Pós-Graduaçã-Rafael Fortuna Pizzi
CNHI – Iveco Latin America-Getúlio Soares Júnior
  • Technical Paper
  • 2019-36-0008
Published 2020-01-13 by SAE International in United States
This study aims at analyzing the causes of noise in a heavy vehicle brake system (6x2 tractor) and proposing solutions to improve comfort during braking as it is known that, during the activation of the automotive brakes, noise can be generated in different frequency bands that can cause discomfort to the user and the study of how to reduce it is considerably important to bring more comfort in its use. As a working methodology, firstly, comparative analysis of dimension and material were performed between the axle assembly that presented noise and another axle assembly of a vehicle with no noise adopted as reference. This information was used as the basis for the frequency and acceleration virtual analysis that were validated with vehicle instrumentation and data acquisition. In parallel, vehicle tests with different brake friction materials were conducted. The answers of the dimension and material analysis from the axles assemblies highlighted the specificities of each of them but did not show great influence in the observed noise incidence. The vehicle instrumentation and data acquisition besides validate…
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Buzz Avoidance on Sunroof Light Sunshades: Design and Validation

Ford Motor Company-Douglas Demori, Marcos Paulo de Oliveira, Rosiane Viegas
MSX International-Douglas França
  • Technical Paper
  • 2019-36-0148
Published 2020-01-13 by SAE International in United States
Sunroof is placed in certain high-end vehicles to give user a better driving experience. All automakers are searching alternatives to reduce weight and cost in the vehicle, in which sunroofs are also impacted. Some alternatives are already applied, as a honeycomb paper used in some sunshades that presents benefits, as less weight and with a good cost reduction. Although, due the reduced weight for this part produced in this material, it shows more susceptibility to reproduce the vibration that vehicle propagates in movement, especially in bad condition roads. The sunroof assembly is dependent of the roof reinforcement and roof skin, but in this special case, the validation could be done in the components itself because the interaction of the sunshades is directly dependent of the other sunroof parts, as rails and front frame. These buzz noise in lights sunshades is perceptible when it is almost or totally close, since lighter material vibrates freely without rail anchorage, then clashing against the front frame surface. Considering the package, the key point is to design the sunshade to…
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Robustness Design to Avoid Noise on Exterior Handle System

Ford Motor Company-Douglas Demori, Júlio Magalhães, Cristiane Carla Gonçalves, Helano Santos
  • Technical Paper
  • 2019-36-0137
Published 2020-01-13 by SAE International in United States
Squeak and rattle are two undesirable occurrences during component operation and during vehicle driving condition, resulting in one of the top complains from costumers. One common grievance could happen during the user exterior handle operation and during side door closing. The exterior handle system during the operation could generate a squeak between interface parts, if materials and geometric tolerances was not been carefully designed. Also, vibration generated during door closing effort, might generate squeak between parts since the reinforcement for exterior handle touches the outer sheet metal internally. For this reason several guidelines might be included to avoid potential noise condition for this system during vehicle lifetime as correct material reduce friction between parts, taking into consideration the geometric condition between parts. Plus, coupling system on handles two pieces should also be evaluated to avoid squeak during use. Not less important, if required anti-shock material system may be applied to eliminate a clash produced between parts during excessive vibration. It is extremely important to evaluate the environment that the vehicle will be exposed since the…
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Influence of Pads and Brake Disc wear on Brake Squeal Noise

Universidade Federal de Minas Gerais / FCA - Fiat Chrysler A-Marco Túlio Batista dos Anjos, Juan Carlos Horta Gutiérrez, Cláudio Junior Ferreto, Felipe Dornellas Silva, Lázaro Valentin Donadon
  • Technical Paper
  • 2019-36-0005
Published 2020-01-13 by SAE International in United States
The present work aims to investigate the influence of wear of the pads and brake disc on the brake squeal behavior with the help of the Finite Element tool. Brake discs basically work by the pressure of the brake pads against a rotating disc. The friction between the pads and the disc causes the latter to decelerate, but it can also cause dynamic instabilities of the system giving rise to noises. Among the main noise in vehicle brake systems, there is the squeal noise, which is usually associated with the coupling of two neighboring natural modes. One possible way to identify unstable modes is by extracting complex eigenvalues from the system. An unstable mode can be identified when, in the result of the extraction of the complex eigenvalues, the real part of the eigenvalue is positive. In the present work, a brake system (disc and positioned pads and their respective materials and friction coefficients) was duly modeled and validated. The validation was done by means of a correlation between the frequency of the noises found…
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Applications of Strain Measurements to Improve Results on Transfer Path Analysis

Centro Federal de Educação Tecnológica de Minas Gerais-C. A. P. Melo
Escola de Engenharia de São Carlos, Universidade de São Paul-A. C. R. Ramos, L.P.R de Oliveira
  • Technical Paper
  • 2019-36-0323
Published 2020-01-13 by SAE International in United States
Vehicles with lower noise levels and better levels of vibratory comfort for passengers made the area of noise, vibration and harshness (NVH) one of the main areas related to the perception of vehicle quality. Several approaches on the contribution of transfer paths have been studied to define the propagation energy in vehicular structures. Transfer Path Analysis (TPA) is a tool to improve NVH performance with the primary goal of reducing and improving perceived vibrations and noise in the cabin vehicle by occupants. Indirect methods are especially important in cases where the force signals are immeasurable in practice in terms of cost and space for sensor couplings, in the measurement configuration, and particularly in the case of distributed forces. The matrix inversion method, perhaps the most popular classic TPA, identifies operational forces using passive body acceleration. However, removal of the source can change the dynamic characteristics of the assembled structure and increase the time of the experiment, which results in misleading information in the measurements. For this reason, the inversion operation of the acceleration matrix can…
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A proposal for semi-analytical model of teeth contact with application to gear dynamics

Politecnico di Torino, Department of Mechanical and Aerospac-Carlo Rosso, Fabio Bruzzone, Tommaso Maggi, Claudio Marcellini
  • Technical Paper
  • 2019-01-2269
Published 2019-12-19 by SAE International in United States
In this paper a semi-analytical (SA) algorithm developed for the solution of the contact problem between two mating spur gears is presented and its application to the study of engagement dynamics is shown. Firstly, a quasi-static two-dimensional (2-D) approach is implemented to solve the contact taking into account several flexibility contributions related to the mating gears. In detail, a modified Hertzian model for the investigation of the real contact area considering the variable curvature of the profiles is developed. A comparison between this model and the classical Hertzian model is shown: the limitations of the classical method, for instance the possibility of analyzing bodies with varying curvatures and the peaks of pressure due to corner contact are therefore overcome. Furthermore, all the different tooth and gear deformations due to the meshing interaction are shown. This allows the computation of the Static Transmission Error (STE), main source of vibration and noise. The influence of tooth profile modifications is also highlighted. A comparison of the calculation of the STE with a Finite Element Method (FEM) model and…
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Technique for Front-loading Countermeasures against Deterioration of Sound Quality in Vehicle Interior due to Rapid Combustion in an SI Engine

Honda R&D Co., Ltd-Kenji Torii, Tatsunori Tsuruta
  • Technical Paper
  • 2019-01-2304
Published 2019-12-19 by SAE International in United States
This paper discusses a technique for the examination of countermeasures at the design stage of the prototype vehicle in order to realize efficient enhancement of the engine combustion noise quality in the vehicle interior. An existing sound quality evaluation method was applied as a simulation technology. The deterioration of the sound quality of combustion noise in the passenger compartment of a new vehicle was estimated from the in-cylinder pressures of a newly developed engine measured on a dynamometer test bench and the structural response functions obtained from the previous mass production vehicle. In addition, the level of reduction in structural response sensitivity necessary for the enhancement of combustion noise quality was estimated for each frequency band. Based on the results, effective countermeasures for the enhancement of combustion noise quality were selected and reflected in the drawings for the initial prototype vehicle. This made it possible to realize the target combustion noise quality in the initial prototype vehicle, which in turn eliminated the necessity for the additional combustion noise countermeasures that have often been applied at…
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Equivalent Radiated Power driven optimization for driveline housings using simulation tools to cut-down the project time

VE Commercial Vehicles, Ltd.-Suresh Kumar Kandreegula, Hemant Nishad, Dheeraj Singh, Kunal Kamal
  • Technical Paper
  • 2019-28-2533
Published 2019-11-21 by SAE International in United States
In the field of Automotive industry, being competitive makes you succeed. Industry is moving towards advancement day by day. New technologies to improve fuel efficiency, crash resistance, vehicle noise levels have been trending. At VECV, we have traditionally worked on CAE of driveline housings (clutch housing & transmission housing) based on static, dynamic and transient loadings. Currently, weight optimization technique depends on the structural and dynamic loading conditions, but do not consider acoustic concerns. Powertrain housings are highly prone to vibrations and leads to high level of noise. Noise has been constant issue in the casting components associated to driveline. There have been lot of research going on to reduce the level of noise and vibrations in the vehicle driveline, which ultimately leads to fuel efficiency and ergonomic benefits. Low noise generation can also lead to saving of lot of resources deployed to dampen the noises. In order to capture the acoustic responses of the system and to improve the design based on acoustic responses, a comprehensive analysis of newly developed driveline housings (clutch housing…
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Lattice Boom Cranes - Method of Test

Cranes and Lifting Devices Committee
  • Ground Vehicle Standard
  • J987_201911
  • Current
Published 2019-11-13 by SAE International in United States
This SAE Standard applies to mobile construction-type lifting cranes utilizing pendant-supported, conventional, and luffing jib type lattice boom crane structures.
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