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NVH benefit of the Frunk

Autoneum Management AG-Federico Di Marco, Flavio Pezzani, Andreas Daving, Luca Mazzarella
  • Technical Paper
  • 2019-01-1456
To be published on 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 non-negligible 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…

Model Verification of CAE with NVH-test Acting on Downsized Car Engines

Automotive Powertrain CAE NVH-Urban Rönnqvist
NVH-testing Powertrain-Janos Ribarits
  • Technical Paper
  • 2019-01-1550
To be published on 2019-06-05 by SAE International in United States
Today’s trend of downsized internal combustion engine development for cars is characterized with; high torque, low engine speed, low weight, high degree of cyclic irregularity, low excitation frequency due to fewer cylinders active e.g. 4-cylinder or less. Torque output 100 Nm at low engine speed 1000 rpm has become normal. This implies in respect of vibrations that it is important to control engine suspension rigid body modes e.g. roll yaw and pith ones. The rigid body modes frequencies should be low so they cannot be reached and induced by the low exciting harmonics of cylinder pressure and mass forces for low engine speeds or idling. Crucial is the rigid body modes in relation to the excitation forces. It is also important to control the overall flexible vibration modes. Our purpose is to describe the method to optimize the powertrain suspension, beginning with modeling/simulation and ending with verifying the vibration level on a real running engine i.e. a Volvo Cars in-line 4-cylinder VEA diesel engine in a test rig/cell. As a method a mathematical CAE model…

Features of Mathematical Modeling in Problems of Determining the Engine Power by the Parameters of the Exhaust Gas Turbocharger

Odessa National Maritime University-Andrii Golovan
  • Technical Paper
  • 2019-01-1497
To be published on 2019-06-05 by SAE International in United States
The features of modeling the working process of a turbocharged marine engine in order to reveal the relationship between the engine power and the operation modes of a gas turbocharger are discussed in the article. Based on the results of modeling, a model was obtained for the dependence of the power of the internal combustion engine on the parameters of the exhaust gas turbocharger operation. As a basic parameter of the gas turbocharger operation, the rotor speed was chosen. The scavenging air temperature is selected as an additional parameter. The article shows the results of experimental studies to determine the performance of a gas turbocharger at various modes of operation of a marine internal combustion engine. The article describes the structure of a diagnostic system that allows recording the operating modes of a gas turbocharger in a non-contact method. The use of experimental data in the verification of simulation results has made it possible to reduce the error in determining the power of an internal combustion engine by 5-10%. The described method for estimating the…

Noise and Vibration End-of-Line Production Testing and Analysis Challenges

Bruel & Kjaer-Chris Moon
  • Technical Paper
  • 2019-01-1464
To be published on 2019-06-05 by SAE International in United States
Theoretical modeling continues to play a larger role in noise and vibration engineering; however, until products are perfectly made, there will be a need to evaluate their end of line (EOL) performance. Manufacturing production of a wide range of items has classically involved some amount of subjective and/or evolved objective quality testing along the line or at the end of the line. This testing can have goals of determining product safety, durability, functionality, or the vibration/sound quality. A vibration-based measurement approach is often used for many of those goals. Often, many modern products utilize some combination of electric motors, internal combustion engines, and power transmission rotational components. The EOL testing for many of these rotational components is after many years now heavily refined in the measurement and analysis methods, and the separation of good, bad and marginally bad samples may not always be challenging. It is frequently the non-standard types of products, either subcomponents or assemblies, which may provide unique challenges to the typical measurement and analysis methods. Additionally, depending on how new the EOL…

Identification of Transfer Path Analysis of Rumbling Noise in a Passenger Car Based on In-Situ Blocked Force Measurement

Hyundai & Kia Corp-Doohee HAN
Hyundai Motor Group-Insoo Jung
  • Technical Paper
  • 2019-01-1587
To be published on 2019-06-05 by SAE International in United States
The control of rumbling noise is one of major targets in control strategies of interior sound quality inside of cabin in a passenger car. For the control of the rumbling noise in a passenger car, at the first, the transfer path of the rumbling noise is should be identified. It had been known that the major source of the rambling noise is due to the combustion force of an engine. The combustion force excites the engine and induces the vibration of the powertrain. The vibration of the powertrain is transferred to the car body throughout the structural transfer path of a car. The vibration of the car body emits the vibra-acoustic noise inside of a car. It has been called the rumbling noise due to structural borne. If there are the structural resonances among the structural paths such as engine, transmission, mount bracket, suspension, and car body, the rumbling noise would be amplified. For the identification of the major resonances on the structural transfer path, the classical transfer path analysis (CTPA) had been used for…

Development of a Muffler Insertion Loss Flow Rig

University of Kentucky-Jonathan Chen, D. W. Herrin
  • Technical Paper
  • 2019-01-1482
To be published on 2019-06-05 by SAE International in United States
Mufflers and silencers are commonly used to attenuate noise sources such as internal combustion engines and HVAC systems. Though the transmission loss of a muffler sans flow is relatively simple to obtain using the two-load method, the presence of mean flow modifies the muffler behavior. The development of an insertion loss test rig is detailed. A blower produces the flow and an upstream silencer quiets the flow before it enters the muffler. Loudspeakers are positioned just downstream of the silencer and they are used as the sound source. The measurement platform allows for the measurement of flow-induced noise in the muffler. In addition, the insertion loss of the muffler can be determined, and this capability was validated by comparison to a one-dimensional plane wave model.

On the Measurement and Simulation of Flow-Acoustic Sound Propagation in Turbochargers

FEV Europe GmbH-Ralf Stienen
Institute for Combustion Engines, RWTH Aachen University-Hendrik Ruppert, Felix Falke, Stefan Pischinger, Marco Günther
  • Technical Paper
  • 2019-01-1488
To be published on 2019-06-05 by SAE International in United States
Internal combustion engines are increasingly being equipped with turbochargers to increase performance and reduce fuel consumption and emissions. Being part of exhaust and intake systems, the turbocharger strongly influences the orifice noise emission. Although 1D-CFD simulations are commonly used for the development of intake and exhaust systems, validated acoustic turbocharger models are not yet state-of-the-art. Consequently, the first aim of the paper is the investigation of the influence on the orifice noise and the development of an accurate 1D-CFD model. Firstly, active and passive acoustics of turbochargers are distinguished. Complex active turbocharger noise emissions were investigated on a turbocharger test rig and could be correlated with unstable rotating stall. Therefore critical acoustic operation can be identified in early engine development stages by comparison to other tested turbochargers. The passive acoustic transmission loss was measured for a wide operating range of four turbochargers, including wastegate and VTG-system variations. Low frequency attenuation is dominated by impedance discontinuities, increasing considerably with mass flow and pressure ratio. High frequencies are determined by destructive interference in the stator. A new…

Test and Analysis of Electromagnetic Noise of an Electric Motor in a Pure Electric Car

Geely Automobile Research Institute-Perry Gu, Chao Gong
Geely Automoile Research Institute-Qiang kang
  • Technical Paper
  • 2019-01-1492
To be published on 2019-06-05 by SAE International in United States
Compared with the low-frequency ignition order of mechanical and combustion noise of the internal combustion engine, the electric drive assembly noise of electric vehicles is mainly the high-frequency whining order noise generated by the electromagnetic force and gear meshing, as well as the high-frequency umbrella noise generated by DC/AC pulse width modulation. Although the radiated sound power is far less than that of an internal combustion engine, the high frequency noise of the motor and the reducer is also annoying. In this paper, the main characteristics of the vibration and noise of an electric motor are obtained by testing it on the vehicle and on the test rig. The main frequency orders are multiplies of motor poles, of which the most significant is the 48th order. The deformation of the motor at the resonance frequency of the 48th order is the breathing mode. Through analysis of electromagnetic force wave, the sources of main orders of motor noise are explained. The most significant order 48th comes from the interaction between rotor magnetic field and stator slots.…


Ford Motor Company-Abdelkrim Zouani
  • Technical Paper
  • 2019-01-1551
To be published on 2019-06-05 by SAE International in United States
Idle combustion stability is a key contributor to Engine Idle Shake and can impact the overall perception of vehicle quality. The sub-firing harmonics of the combustion torque are used as a metric to assess idle shake and are, typically, measured at different levels of engine break mean effective pressure (BMEP). Due to the nature of the combustion phenomena at idle, it is clear that predicting the distributions of cycle-to-cycle and cylinder-to-cylinder combustion pressure, required to assess the combustion uniformity, cannot be achieved with the state of the art simulation technology. Inspired by the advancement in the field of machine learning and artificial intelligence and by the availability of a large amount of measured combustion pressure data, this paper explores the performance of various machine learning algorithms in predicting the idle combustion uniformity. The algorithms that are explored include Neural Network (NN), Support Vector Machine (SVM), Ensembles of Trees (EOT) and Gaussian Process (GP). The variables selected as inputs to these algorithms include BMEP, indicated mean effective pressure (IMEP), pumping mean effective pressure (PMEP), spark timing,…

Improved measurement procedures for engine noise reduction with advanced microphones

GRAS Sound & Vibration-Jan Hansen, Per Rasmussen
  • Technical Paper
  • 2019-01-1463
To be published on 2019-06-05 by SAE International in United States
Introducing a new transducer concept has resulted in considerable reduction in setup time and at the same time improved accuracy and repeatability for engine bay noise transfer studies. The acoustic environment inside cars are one of the primary comfort parameters. This is made up of a number of contributions from drivetrain, auxiliary equipment, wind noise and tire noise, and all are influenced by the transfer from the source to the receiver. With the change from purely internal combustion engines to electrical or electrical assisted propulsion systems, a new set of noise sources are introduced in the engine compartment and this requires renewed focus on the transmission paths to the receivers inside the car cabin. Typically, one of the tools to study these mechanisms is by using a reverse transmission technique, placing a well-defined sound source in the receiver position inside the car and measure the resulting sound pressure levels in the engine compartment. Assuming reciprocity, these measurements can be used to estimate the attenuation of transmission from sound sources in the engine compartment to the…