A study of engine noise transmission using statistical energy analysis

Abstract

This work uses statistical energy analysis (SEA) to study engine noise transmission through a small passenger motor vehicle and in order to do this the sound and vibration power input is calculated. An aim of this work is to identify the causes of differences between measured and SEA predicted vibration transmission in motor vehicles. To allow this to be studied a relatively simple running condition and vehicle are chosen. Airborne and structural paths for sound and vibration transmission to a vehicle saloon are considered. Also, SEA is used to identify the relative importance of each structural and airborne power input in relation to the sound power that is transmitted to the vehicle saloon. This technique can then make it possible for the power input matrix to be greatly simplified. The most important power input to the small passenger vehicle used in this study is found to be at the floor mounts of the engine subframe. At high frequencies resonant transmission through the firewall (dash) can also be important. The results indicate the difficulty of estimating the power input, which is the main cause of differences between measured and predicted results (even for the restricted running condition considered here). The work also demonstrates that SEA can be very useful for identifying important transmission paths and predicting overall performance.

A study of exhaust noise in a motor vehicle using statistical energy analysis

“…Each wave type can be considered separately so that, for example, any given plate can support vibration associated with three subsystems. In this case, an SEA model that only considers bending wave transmission will be considered, where coupling loss factors are calculated using methods used by Steel [3,4] and applying the theories presented by Cremer et al [7], Lyon [8], Mees and Vermeir [9] and Craik [10].…”

“…Statistical energy analysis (SEA) is being used extensively in the motor vehicle industry as a tool for the identi®cation of noise problems [1±3] and paths of vibration transmission [1,4] and for the appraisal of likely eects of design changes [5]. The aims of the present work are to extend previous work by Steel [3,4] to include airborne noise transmission and to include structural and airborne¯anking paths for transmission through an exhaust system and through the¯oor of the vehicle, and to demonstrate the practical application of SEA to a real noise problem in a commercial vehicle.…”

“…An SEA model of the vehicle is developed in the same way described for another type of vehicle by Steel [3,4]. In that work the vehicle considered was constructed from glass-®bre reinforced plastic (GRP) and the poor design of the engine subframe and connection to the vehicle body resulted in structural power inputs dominating sound transmission to the vehicle saloon.…”

“…In earlier work, Steel [4] demonstrated ways of estimating structural vibration power input to a vehicle at the mount points of an engine subframe to a vehicle structure. In the present work, these methods for estimating power input are applied to a commercial vehicle with the engine running, but the design of the vehicle is more complicated.…”

Estudio CFD de la resonancia en la cámara de combustión de Motores Diesel HDI

“…En efecto, tal y como se ha visto en el apartado 2.3.3, en el caso de estudios en motor de automóvil, el método FEM ha demostrado tener resultados fiables hasta 500 Hz aproximadamente. Para mayores rangos de frecuencia, se están estudiando otros métodos más aproximados, como el Análisis Estadístico de Energía (SEA) [26,45,94,174], en el cual se modela un sistema como un montaje de sub-sistemas, a los cuales se asigna una variable de respuestaúnica correspondiente a la energía vibracional [95].…”