This Engineering Academy covers a variety of vehicle noise control engineering principles and practices. Two specialty tracks are available: Vehicle Interior Noise and Powertrain Noise. While the Powertrain Noise track focuses on NVH issues generated by powertrain noise sources and the design strategies to minimize them, the Vehicle Interior Noise track focuses on the understanding and application of acoustical materials to optimize NVH in the passenger or operator compartment of a vehicle. Considerable attention is given to current measurement and instrumentation technologies and their effective use.
This Engineering Academy covers a variety of vehicle noise control engineering principles and practices. Two specialty tracks are available: Vehicle Interior Noise and Powertrain Noise. While the Vehicle Interior Noise track focuses on the understanding and application of acoustical materials to optimize NVH in the passenger or operator compartment of a vehicle, the Powertrain Noise track focuses on NVH issues generated by powertrain noise sources and the design strategies to minimize them. Noise sources include engines, transmissions/transfer cases, accessories, exhaust, gears, axles, joints, and couplings.
Brake noise is one of the highest ranked complaints of car owners. Grunts, groans, squeaks, and squeals are common descriptions of the annoying problem which brake engineers spend many hours trying to resolve. Consumer expectations and the high cost of warranty repairs are pushing the optimization of brake NVH performance. This course will provide you with an overview of the various damping mechanisms and tools for analyzing and reducing brake noise. A significant component of this course is the inclusion of case studies which will demonstrate how brake noise squeal issues have been successfully resolved.
This four-session web seminar provides a detailed understanding of the source - path-receiver relationship for developing appropriate sound package treatments in vehicles, including automobiles, commercial vehicles, and other transportation devices. The course provides a detailed overview of absorption, attenuation (barrier), and damping materials and how to evaluate their performances on material, component, and vehicle level applications. A significant part of this course is the case studies that demonstrate how properly designed sound package materials successfully address vehicle noise issues.
This web seminar provides an in-depth overview of diesel engine noise including combustion and mechanical noise sources. In addition, the instructor will discuss a system approach to automotive integration including combining sub-systems and components to achieve overall vehicle noise and vibration goals.
Drivetrain noise from heavy off-road vehicles mainly includes engine noise, drive shaft noise, wheel-side gear noise, tire pattern noise etc. They are the main noise source for such vehicles as they greatly influence the ride comfort of the passengers inside. This paper solved the drivetrain noise problem of a heavy off-road vehicle using the method of active noise control. Firstly, the vehicle is benchmarked and the noise problems are analyzed, while the noise sources are identified by analyzing the transmission principles of the drivetrain; secondly, active noise control strategies are made for the vehicle based on the noise profiles under various operating conditions; thirdly, the multiple parameters for active noise control are computed from simulations modeling the vehicle in idle, constant speed and acceleration respectively; lastly, road tests are conducted using the multiple parameters from the simulations and a noise reduction of 2-4 dB can be achieved in the whole vehicle.
Buses have become one of the most widely used mode of public transportation, particularly for city applications. Indeed, passenger comfort and vehicle noise are a major concern faced by automotive industry. Brake system is one such contributor to undesired vibrations and obnoxious noise. Squeal noise, caused due to friction-induced vibrations, is a serious customer irritant to the bus passengers as well as the environment, also leading to brake performance deterioration and monetary abominations in terms of warranty costs. Brake squeal noise has been considerably studied for over years. Several design modifications and structural changes have been incorporated to prevent the occurrence of squeal noise, but the issue persists. In this paper, we have discussed on brake squeal noise reduction in city buses by optimisation brake drum diameter, selection of different friction liner linings and optimising other brake components sizes. Keywords: Squeal, brakes, drum, vibration, bus, comfort
Exhaust muffler is the most important component for overall vehicle noise signature. Optimized design of exhaust system plays a vital role in engine performance as well as auditory comfort. Exhaust orifice noise reduction is often contradicted by increased back pressure and packaging space. The process of arriving at exhaust design, which meets packaging space, back pressure and orifice noise requirements, is often manual and time consuming. Therefore, an automated numerical technique is needed for this multi-objective optimization. In current case study, a tractor exhaust system has been subjected to Design of Experiments (DoE) using SOBOL sequencing algorithm and optimized using NSGA-II algorithm. Target design space of the exhaust muffler is identified and modeled considering available packaging constrain. Various exhaust design parameters like; length of internal pipes, location of baffles and perforation etc. are defined as input variables.
A growing development of hybrid or fully electrical drives increase demand for accurate prediction of noise and vibration characteristic of electric and electronic components. This paper describes the numerical and experimental investigation of noise emission from power electronics, as a one of the new important noise sources in electric vehicles. Emitted noise from the printed circuit board (PCB) equipped with multi-layer ceramic capacitors (MLCC) is measured and used for calibration and validation of numerical model. Material properties are tuned using results from experimental modal analysis with special attention on orthotropic characteristic of PCB glass-reinforced epoxy laminate sheet (FR-4). Structural vibrations are calculated with commercial FEM solver with modal frequency response analysis. Sound radiation is simulated using the wave based approach. Simulation and experimental results are compared in frequency range up to 10 kHz.
The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle-level fuel consumption. Specifically, the use of electrified propulsion systems is expected to play an increasingly important role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. This will also include a strong growth in the demand for electric drive units (EDU). The change from conventional vehicles to vehicles propelled by EDU leads to a reduction in overall vehicle exterior and interior noise levels, especially during low-speed vehicle operation. Despite the overall noise levels being low, the NVH behavior of such vehicles can be objectionable due to the presence of tonal noise coming from electric machines and geartrain components. In order to ensure customer acceptance of electrically propelled vehicles, it is imperative that these NVH challenges are understood and solved
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.
Automotive industry is facing new NVH challenges due to the emergence of hybrid and electric vehicles. In these vehicles, because of the absence of the dominant noise source from internal combustion engine many other sources become unmasked. In addition, new noise sources are generated by the electric powertrain system. One of the important noise sources is the electric motor of the electric powertrain system. The present work is directed towards the application of numerical simulation methods for the evaluation of automotive interior noise due to an electric motor. Specifically, the interior noise of a typical automotive cabin is evaluated numerically. In the first phase, electromagnetic simulation is performed to evaluate the transient (Maxwell) forces on the teeth of the stator of the motor. Subsequently, the forces are transformed to frequency domain and applied to calculate the motor vibration using structural dynamic analysis.
This paper is aimed at studying the NVH and acoustic performance of a 3-phase AC induction motor in order to find a way to reduce the magnetic component of noise from an electric motor in an electric vehicle (EV). The method suggested here is to reduce the magnetic component of sound from the motor by making modifications to the end bracket of the motor housing. EVs are being considered the future of mobility mainly owing to the fact that they are environment-friendly. With a lot of companies already investing heavily in this technology, electric drives are set to become extremely popular in the years to come. The heart of an EV is its motor. Modern electric vehicles are quiet and with the lack of an IC engine to mask most sounds from other components, the sound from the electric motor and other auxiliary parts become more prominent. This paper lays down a process to analyze the sound radiated from the electric motor in three broad steps.