Caracterización de la respuesta acústica de sistemas de post-tratamiento

Abstract

[EN]

Nowadays, acoustic pollution has reached noxious levels, and it has even been declared as the third cause of environmental mortality by the World Health Organization, right after air pollution and indirect exposition to tobacco. This is why over the last decades the European Union has implemented several measures for reducing noise levels across its territory. Among these measure, there is the approval of progressively more restrictive laws on the permitted noise level for vehicles. The increasing restrictions have forced manufacturers to implement some changes, the mu er being one of the systems a ected. Until now, mu ers were designed considering the conditions of the exhaust gas at the outlet of the exhaust manifold as the inlet boundary conditions. However, over the last years the European Union has also limited the emissions levels allowed, leading to the placement of after-treatment systems between the exhaust manifold and the mu er. The presence of these systems a ects the uid-dynamic conditions of the exhaust gases, thus making the mu er work in an operation point di erent to the optimum for which it was designed. This forces the necessity of studying the acoustic behaviour of the after-treatment systems in order to consider them for the mu er's design. This report is part of a project focused on the acoustic characterization of those mentioned after-treatmente systems. The characterization is done by testing the systems in three di erent facilities: continous ow test rig, impulse test rig, and hot pulsating ow test rig. With these experimental measurements, the transfer matrix of each system can be obtained, completely de ning its acoustic behaviour. More speci cally, this work is focused on characterizing the behaviour of the after-treatment system when there is presence of soot particles in the lter's channels.

[ES] El uso de sistemas de post-tratamiento de gases de escape en motores de combustión interna alternativos es hoy en día indispensable debido a las restricciones impuestas a la emisión de contaminantes. Al estar estos sistemas posicionados aguas arriba del silenciador se hace necesario caracterizar el efecto de atenuación sobre la emisión acústica antes de la entrada a éste con el fin de optimizar el diseño acústico de la línea de escape. En este trabajo se pretende caracterizar la respuesta acústica de diferentes sistemas de post-tratamiento (DOC, DPF, SCR¿) por medio del análisis de resultados experimentales obtenidos bajo diferentes condiciones de operación.