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The current trend toward hybrid and electric automotive powertrains increases the complexity of the vehicle development and integration work for the NVH engineers. For example, considering that the combustion noise is reduced or absent, secondary noise sources like drivetrain, auxiliary systems, road and wind noise become of relevance in terms of vehicle noise comfort. This trend combined with the shortening of vehicle development cycle, the increased number of vehicle variants and an increasingly competitive marketing landscape, force engineers to front-load their design choices to the early stages of the development process using advanced engineering analysis tools. In this context, innovative technologies such as Virtual Prototype Assembly (VPA) and NVH simulator provide the right support to the engineer’s needs when developing the vehicles of the future.

E-motors are characterized by their high-frequency content. This brings a new challenge for a technology such as Component-based Transfer Path Analysis. This paper will intend to show how this modular methodology has been applied for a wiper e-motor. The source is characterized in-situ by a set of blocked forces and alternatively with pseudo forces. Afterward, the independent loads are converted to contact forces using a Frequency Based Substructuring technique, allowing assembly definition and target prediction on a different receiver. Finally, the predicted vibrations on the target assembly are compared to the measured one for validation purposes. A dedicated high-frequency shaker was developed to meet the required data quality. In this way the substructuring technique was applicable in a wide frequency range up to 5 kHz.

Road induced noise is getting more and more significant in context of the electrification of the powertrain. The automotive industry is seeking for technologies to predict the contribution of vehicle components upfront, early in the development process. Classical Transfer Path Analysis (TPA) is a well-established technique that successfully identifies the transmission paths of noise and vibration from different excitation sources to the target responses. But it has a drawback: it requires the physical availability of the full vehicle. To achieve shorter development cycles, to avoid costly time-consuming design iterations and due to the limited availability of prototypes, engineers derived a method that addresses these requirements.

The noise radiated by an ICE engine results from a mixture of various complex sources such as combustion, injection, piston slap, turbocharger, etc. Some of these have been categorized as combustion related noise and others as mechanical noise. Of great concern is the assessment of combustion noise which, under some operating conditions, is likely to predominate over the other sources of noise. The residual noise, produced by various other sources, is commonly referred to as mechanical noise. Being able to extract combustion and mechanical noise is of prime interest in the development phase of the engine and also for diagnostic purposes. This paper presents the application of combustion mechanical noise separation techniques on a V8 engine. Three techniques, namely the multi regression analysis, the classical Wiener filter and the cyclostationary (synchronous) Wiener filter, have been investigated.

In the context of the reduction of traffic-related noise the research reported in this paper provides tools that could be used to develop low noise tyres. Two measurement techniques have been analyzed for exterior noise radiation characterization of a loaded rotating slick tyre on a rough road surface. On one hand sound pressure measurements at low spatial resolution with strategically placed microphones on a half-hemisphere around the tyre/road contact point have been performed. This technique provides a robust solution to compute the (overall) sound power level. On the other hand sound intensity measurements at high spatial resolution by means of a scanning intensity probe have been performed. This technique allows a more detailed spatial visualization of the noise radiation and helps in getting more insight and better understanding of the acoustical phenomena.

Certification of vehicle noise emissions for passenger vehicles, motorcycles and light trucks is achieved by measuring external sound levels according to procedures defined by international standards such as ISO362. The current procedure based on a pass-by test during wide-open throttle acceleration is believed far from actual urban traffic conditions. Hence a new standard pass-by noise certification is being evaluated for implementation. It will put testing departments through their paces with requirements for additional testing under multiple ‘real world’ conditions. The new standard, together with the fact that most governments are imposing lower noise emission levels, make that most of the current models do not meet the new levels which will be imposed in the future. Therefor automotive manufacturers are looking for new tools which are giving them a better insight in the Pass-by Noise contributors.