Abstract
Diesel particulate filter is impedance to elastic wave. In order to promote the anechoic performance of diesel particulate filter in designing process, the acoustic characteristics of which were analyzed on the basis of acoustic four-terminal method. The transfer matrix of simplified diesel particulate filter structure was derived to construct the acoustic simulation model, and a two-load experiment of impedance tube was implemented to calibrate the simulation model. On this basis, the correlation between diesel particulate filter structural parameters and acoustic characteristics was investigated. The results show that the transmission loss is sensitive to porosity, gap, layer thickness, and aspect ratio of porthole for a certain diameter diesel particulate filter. Furthermore, two types of diesel particulate filter structures which were octagonal inlet matches square outlet and asymmetric square channels possess superior noise elimination effect compared with the traditional square channel types. At a certain frequency range, the peak noise was reduced by 2–3 dB. The study could provide guidance to the designing of diesel particulate filter anechoic performance.
Highlights
The wall-flow diesel particulate filter (DPF) is a kind of honeycomb structure made of ceramic cordierite or silicon carbide; the ends of all channels in particulate filters are alternatively plugged
Acoustic response of exhaust gas would change after traversing the DPF; in addition, the variable properties of the porous substrate would play an important role on the acoustic characteristics.[1]
The reduction of the exhaust noise from diesel engine is mainly managed by proper exhaust silencer design, while less attention is paid to the acoustic performance of the after treatment devices (ATD)
Summary
The wall-flow diesel particulate filter (DPF) is a kind of honeycomb structure made of ceramic cordierite or silicon carbide; the ends of all channels in particulate filters are alternatively plugged. Outlet sound pressures of particulate filter by simulation were substituted in equation (11) to calculate the transmission loss. Equation (9) showed that transfer matrix was relevant to cross-sectional area and length of particulate filter. Equation (19) showed that transmission loss was relevant to impedance and inlet and outlet acoustic pressures of particulate filter. The inlet and outlet acoustic pressures were measured to derive transfer matrix, calculating transmission loss. The work discussed the effect of the conductivity, cavity volume, and cross-sectional area of the particulate filter to the transmission loss based on research of acoustic performance by controlling inlet and outlet pressures. The structural parameters were altered to change the inlet and outlet pressures, influenced transmission loss of the particulate filter. For the structure with lower transmission loss, the valley value had larger increasing rate
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