Modeling of Engine Exhaust Acoustics

Morel, Thomas; Silvestri, John; Goerg, Karl-Alfred; Jebasinski, Rolf

doi:10.4271/1999-01-1665

Cited by 35 publications

(9 citation statements)

References 7 publications

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“…Some of these types of software used by researchers are AVL-BOOST, WAVE, GT-Power and LAMPS and are based on the one-dimensional plane wave and the quasi-three dimensional theory for the prediction of exhaust noise. [4][5][6][7][8] However, from a sound perception viewpoint, researchers have studied the sound quality metrics for some of these predicted values of the exhaust noise and also the measured values of the exhaust noise. It is seen from the literature that there is scope to alter the muffler dimensions to achieve the optimum sound quality based on a jury evaluation.…”

Section: Introductionmentioning

confidence: 99%

A new sound quality metric for the design of engine exhaust mufflers

Reddy

Fatima

Mohanty

2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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In this paper, a study is made to determine the critical dimensions in the design of a family of reactive mufflers which significantly affect the sound quality of the tailpipe radiated noise. The sound quality parameters of the tailpipe noise such as the loudness level, the roughness and the tonality are measured, and a new sound quality metric is developed which can be used as an index to predict the performance of a muffler. The new sound quality metric was based on the evaluations of the synthesized tailpipe noise by a jury consisting of a few undergraduate and postgraduate students at the Indian Institute of Technology Kharagpur. Using the new sound quality metric, the parameters with the most influence on the design of the muffler can be determined. It was found that the length and the open area ratio of a concentric-tube resonator muffler have the highest impact on the tailpipe noise sound quality.

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Section: Introductionmentioning

confidence: 99%

A new sound quality metric for the design of engine exhaust mufflers

Reddy

Fatima

Mohanty

2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…Certain components, however, such as the intake and exhaust manifolds, exhibit a high degree of geometric complexity, which cannot be accurately modelled by 1D codes, unless equivalent 1D models are adopted. The need of achieving good accuracy, along with acceptable computational runtime, has given the spur to the development of simplified geometry based tools, such as quasi-3D and 1D-3D approaches [10,11,12,13,14].…”

Section: Introductionmentioning

confidence: 99%

Fluid Dynamic and Acoustic Optimization Methodology of a Motorbike Intake Airbox Using Multilevel Numerical CFD Models and Experimental Validation Tests

Montenegro¹,

Torre²,

Cerri³

et al. 2013

SAE Int. J. Engines

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In this work a multilevel CFD analysis have been applied for the design of an intake air-box with improved characteristics of noise reduction and fluid dynamic response. The approaches developed and applied for the optimization process range from the 1D to fully 3D CFD simulation, exploring hybrid approaches based on the integration of a 1D model with quasi-3D and 3D tools. In particular, the quasi-3D strategy is exploited to investigate several configurations, tailoring the best trade-off between noise abatement at frequencies below 1000 Hz and optimization of engine performances.Once the best configuration has been defined, the 1D-3D approach has been adopted to confirm the prediction carried out by means of the simplified approach, studying also the impact of the new configuration on the engine performances. The calculations have been further validated by an extensive experimental campaign carried out not only on the test bench for engine performance analysis but also on an acoustic test bench developed by the University of Florence. The experimental acoustic characterization is based on the Multi-Microphone Technique, which guarantees a wider reliable frequency range of analysis and lower errors in the evaluation of the acoustic properties of the examined devices (such as mufflers or intake lines, etc.).Results of the calculations on both the baseline and optimized configurations have been compared to the measured acoustic performance carried with null flow conditions showing an encouraging agreement.

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“…13–14 The prediction of the steady-state and transient behavior of the engine air path system is typically done through the use of detailed one-dimensional models, often referred to as gas dynamic models or wave action models (WAM), for their ability to predict the pressure wave propagation effects that influence the engine volumetric efficiency (VE). 15–20 Such models describe the engine gas exchange process from its physical foundations, based on the mass, momentum and energy conservation equations for one-dimensional unsteady compressible flow. The characterization of the intake and exhaust system is typically coupled by zero-dimensional thermodynamic models for the in-cylinder processes, either based on single-zone or multi-zone combustion models.…”

Section: Introductionmentioning

confidence: 99%

“…Several models have been proposed in the literature for engine system simulation for design and control applications, 15,16,18–24 and well-established commercial tools are also available, see e.g. Morel et al 17 Most of the above models employ numerical solution methods based on different domain discretization arrangements and resort to specific time marching and space integration techniques. In particular, explicit finite-difference methods (FDMs) and finite-volume methods (FVMs) are historically applied for the solution of mass, momentum and energy conservation equations for unsteady flows.…”

Section: Introductionmentioning

confidence: 99%

Modeling wave action effects in internal combustion engine air path systems: comparison of numerical and system dynamics approaches

Stockar

Canova

Guezennec

et al. 2012

International Journal of Engine Research

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The challenge of continuously improving engine fuel economy and emissions has pushed the automotive industry to adopt more efficient procedures for modeling, system simulation and model-based control. Such procedures require accurate and computationally efficient engine system simulation models that are able to predict the cylinder charge composition and the thermodynamic conditions. To this extent, reduced-order models for unsteady compressible flow systems, namely models derived from the fundamental conservation laws without over-simplifying the topology of the engine air path, are receiving considerable interest for performance simulation and control design.This paper presents a comparative study on modeling approaches for the prediction of one-dimensional unsteady compressible flow in the internal combustion engine air path system. Specifically, the paper compares a well-known second-order, shock-capturing finite-difference scheme with two novel solution methods, namely a finite-volume method and a model-order reduction method. The study aims at evaluating the ability of each method to trade-off the prediction accuracy and robustness with the computation time, in light of potential applications to real-time simulation. This is achieved by increasing the discretization length of each method, and evaluating the accuracy of the predicted response in the time and frequency domain.The characterization of the intake and exhaust flows in the manifolds of a single-cylinder engine is considered as a case study. The results are compared for the three solution methods at different discretization lengths to evaluate the ability of each model to retain accuracy and robustness. The computation times of the different methods are also evaluated.The results presented in this paper establish a clear trade-off between accuracy, stability and computation time for each solution method. This allows one to formulate considerations on the advantages and disadvantages of each method in light of potential applications to engine performance prediction, optimization and control design.

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Modeling of Engine Exhaust Acoustics

Cited by 35 publications

References 7 publications

A new sound quality metric for the design of engine exhaust mufflers

A new sound quality metric for the design of engine exhaust mufflers

Fluid Dynamic and Acoustic Optimization Methodology of a Motorbike Intake Airbox Using Multilevel Numerical CFD Models and Experimental Validation Tests

Modeling wave action effects in internal combustion engine air path systems: comparison of numerical and system dynamics approaches

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