Theoretical and experimental investigations on diesel particulate filters

Driven by emission regulations, a diesel Particulate Filter (DPF) is a very important part in the after-treatment device to reduce the harmful particulate matter (PM) from diesel engines. DPF used in the vehicle will result in the change of the acoustic characteristic of exhaust system. Therefore, the sound attenuation, along with pressure drop and filter efficiency, need to be considered during the design of DPF. Due to the structure complexity of DPF and particularity the operating conditions, prediction of acoustic parameters in analytical methods is limited to a narrow band of low frequencies. The simplified method of the three-dimensional acoustical model of DPF is applied in this paper, and its acoustical characteristics are analyzed using SYSNOISE software. The transfer matrix of the DPF is calculated and viscosity correction is added to the transfer matrix. In addition, the insertion loss for operating conditions of the diesel engine is calculated by using the transfer matrix. The significant effect of a viscosity correction on acoustic analysis of DPF is confirmed. In an semi-anechoic laboratory the engine test-bed is established, and the insertion loss of DPF is measured during selected operating conditions of the engine. The comparison between experimental and calculated results validates the acoustical model, and provides a theory basis for optimizing the DPF design.