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Acoustics and Drivability as the Main Drivers for Customer Satisfaction for electrified 2-Wheeler

AVL List GmbH, Austria-Christian Hubmann, Patrick Falk, Bernhard Graf, Hubert Friedl
  • Technical Paper
  • 2019-32-0525
To be published on 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Along with the global trend for electrification, also motorcycle industry is entering new spheres of highly advanced products and is increasing customer demands for electric mobility. Beside hard facts such as performance, driving range, durability and ease of use, also the brand specific attributes such as styling, driveability and even sound for electrified 2-wheeler are very emotional, unique selling prepositions. To determine the subjective parameters for driveability and acoustics, AVL has developed dedicated tools and methods to quantify these attributes with high maturity.In terms of acoustics and NVH there are several crucial noise sources within electrified powertrains, which have to be treated with high attention from the initial development phase to avoid any kind of unforeseen annoyances: E-motor with inverter, transmission and secondary drive are most relevant. This issue becomes even more important with the ongoing market trend of products featuring increased power.Electrified motorcycles commonly are expected to offer supreme acceleration performance, but even this attribute may lead into driver's disappointment if throttle response and overall vehicle driveability parameters are inhomogeneous. The driveability and the…
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Independent Aftermarket (IAM) and the Three Dimensions of Friction Material Evaluation

LINK South America-Pedro Oliveira, Henrique Rodrigues, Eduardo Ferro
  • Technical Paper
  • 2019-36-0006
Published 2020-01-13 by SAE International in United States
It is well known the difference between development levels and engineering investment applied to passenger car brake pads when compared to Original Equipment Manufacturer (OEM) and items sold in the Independent Aftermarket (IAM). Based on these differences, the objective of this paper is to propose a simple evaluation for the IAM that can provide at least some level of the understanding of frictional material behavior. Based on a tripod of variables, or three Dimensions Development, described in this work as Performance, Comfort (NVH) and Durability; and using internationally and established testing procedures to measure these dimensions in order to meet the IAM demands for the cost-benefit engineering investment. An important part of the proposed tool is to position friction material against competition for market known issues, and, more importantly, to ensure end product safety and reliability.
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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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Effective Powertrain Isolation of Off-Highway Vehicles

John Deere Technology Center-Devendra Mandke, Balavardhan Reddy Dasabai, Sandeep Burli
Vellore Institute of Technology-Pushpak Sakhala, Sharan Chandran
Published 2019-10-11 by SAE International in United States
A Powertrain is one of the major sources of excitation of a vehicle vibration and noise in off highway vehicles. It typically has a significant contribution in whole vehicle NVH characteristics. The structure borne energy of the powertrain is transmitted to the chassis and rest of the vehicle through powertrain mounts. Hence, it is of prime importance to design an effective powertrain mounting system in such a way that it will reduce vehicle vibrations to improve vehicle NVH as well as ride comfort, resulting in an effective vibration isolation system and ensuring long service life. In this paper, a newly developed an analytical tool for effective design of isolation system is discussed. For this model, powertrain is considered as a six degree-of-freedom system. Analytical calculations are implemented to find optimum mount design parameters i.e. stiffness, orientation and position of isolators to meet desired NVH targets. To achieve a good isolation characteristic, there is a necessity of decoupling of rigid body modes using optimization of various decoupling methods, which further helps in reducing the forces transmitted…
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Optimizing NVH for EVs

Automotive Engineering: October 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP10_03
Published 2019-10-01 by SAE International in United States

Unique acoustic and harmonic challenges require an integrated approach to simulation and analysis. An expert at Adaptive Corp. explains.

Despite global sales market share stuck at single-digit levels, electric vehicles (EVs) are steadily filling the development pipelines at major OEMs. And as engineers are acutely aware, EVs bring a paradigm shift in the noise, vibration and harshness (NVH) arena. Their harmonic spectra are dramatically different than those of even the smoothest, most refined combustion-engine vehicles and hybrids.

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GKN spreads premium propshaft tech to quiet pickup cabins

Automotive Engineering: October 2019

Stuart Birch
  • Magazine Article
  • 19AUTP10_11
Published 2019-10-01 by SAE International in United States

It may seem a long way in engineering and NVH terms from premium European cars such as Audi's A5 and A7 to light duty trucks, but GKN Automotive has bridged that gap with its latest lightweight all-wheel drive (AWD) modular propshaft. Many pickups suffer a significant amount of unwanted NVH emanating from the front propshaft, with its two universal or CV joints and an interconnecting shaft positioned below and close to the passenger cabin. But now GKN Automotive has “re-characterized” its premium car driveline system to an entirely different vehicle category.

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The Influence of Differential Pad Wear on Low-Frequency and High-Frequency Brake Squeal

SKR Consulting Inc.-Seong K. Rhee
Technische Universitat Braunschweig-Johannes Otto, Georg-Peter Ostermeyer
Published 2019-09-15 by SAE International in United States
The NVH behavior of disc brakes in particular, is in the focus of research since a long time. Measurements at a chassis dynamometer show that brake pad wear has a significant influence on the occurrence of low- and high-frequency squealing [1]. It is suspected that high-frequency squealing is more likely to occur when the wear difference between the inner and outer brake pad is small. In the other case, if the differential wear rate between the inner and outer pads becomes higher, the prevalence of low-frequency squealing increases.In order to examine this hypothesis, this work focuses on a simplified model of a commercial brake system [2]. In a first step, the inner pad’s wear is iteratively increased, while the wear on the outer pad remains unaffected. In a second step, the coefficient of friction at the worn pad is iteratively increased to investigate the influence on the low and high-frequency squealing. With the aid of the Complex Eigenvalue Analysis (CEA), the real part of the eigenvalue is used as a quantification measure in order to…
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Frequency Inspection of Brake System Components

Signalysis Inc.-Robert Cagle
Published 2019-09-15 by SAE International in United States
Frequency inspection has long been a tool utilized by manufacturers of brake system components as a means of quality control. This is important to combat perceived defectiveness of a system that experiences issues, such as brake squeal, as well as to identify actual defects in the parts going out to customers. Every component has its own resonance frequencies based on the dynamics of that component. Knowledge of the resonance frequencies of each component provides insight that can prevent manufacturers from sending out defective units, whether they be perceived defects or actual defects. NVH engineers who understand these phenomena perform theoretical analysis and acquire experimental data in the lab to gain insight into their parts that will eventually be produced on the assembly line. Unfortunately, the frequency requirements, and the consequences thereof, defined by the NVH engineers can still remain somewhat of a mystery to the manufacturing engineers who are tasked with applying them. Oversights in specifications can lead to avoidable scares that lead to delays and downtime. For example, differences in accelerometer placement on a…
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Benefit of a Lightweight Frunk

Autoneum Management AG-Federico Di Marco, Flavio Pezzani, Andreas Daving, Luca Mazzarella
Published 2019-06-05 by SAE International in United States
Due to the increasing number of battery electric vehicles (BEVs), the engineering fields regarding driving comfort and NVH issues are becoming more and more challenging: many new factors affect the development of BEVs NVH package. The noise sources related to the powertrain are different from the traditional ones of internal combustion engines, for instance due to the presence of tonal components, strong harmonics and potential whining noise.To satisfy NVH specifications and the need for lightweight solutions to increase driving range, it is important to mask as much as possible the noise coming from the engine bay with materials both lightweight and acoustically performing. Moreover, for electric vehicles new interesting solutions are possible with the introduction of new components that do not find room under the hood of ICE or hybrid vehicles. These components, if properly designed, could lead to significant NVH benefits. The present paper reports the NVH effects of one of these new components, the frunk, a small compartment inside the engine bay, functionally similar to the trunk.In this paper, the design-by-simulation of a…
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Role of Dynamic Stiffness in Effective Isolation

Deere & Company-Yuzhen Yang
John Deere India Pvt, Ltd.-Balavardhan Reddy Dasabai
Published 2019-06-05 by SAE International in United States
In any machinery, avoiding noise and vibration completely is a difficult task due to the structural dynamic behaviors of components. To safeguard the operator, it is important to best isolate the operator station from NVH environment. Cabin isolation is an important aspect to minimize structure borne noise and tactile vibrations to be transferred into the cabin. Isolators are selected based on the isolation system inertial properties at mounting locations in the operating frequency range interested. The most important assumption to select isolators are that the active side and passive side of the isolators are nearly rigid so impedance mismatch is created for effective isolation.This paper describes the importance of dynamic stiffness of the structures on both the active and passive side for better NVH performance. NVH performance of passive side is evaluated analytically and computationally in terms of tactile vibrations and structure borne noise for various ratios of the dynamic stiffness over isolator stiffness. The isolator selection criterion is also discussed based on rigid body modes, operating frequency range, transmissibility ratio, and kinematic energy distributions.
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