Method for calculating radiation noise of silencer of exhaust system

Abstract

The invention discloses a method for calculating radiation noise of a silencer of an exhaust system. The method comprises the following steps: S1, extracting a static pressure curve of each cavity inthe silencer to be analyzed from simulation software; S2, performing pretreatment through a conversion tool completed during analysis process development, and converting static pressure into frequencyspectrum excitation; S3, conducting finite element modeling on the silencer, and making frequency response calculation; S4, extracting a calculation result, and synthesizing the calculation result into a waterfall plot and a total sound pressure curve; S5, evaluating the total sound pressure curve and the waterfall plot, if the total sound pressure curve and the waterfall plot do not pass the evaluation, returning to the adjustment structure, and starting evaluation again from the step S1; and if so, completing the step of analyzing the radiation noise of the silencer, and then entering a sample piece manufacturing stage. Compared with the prior art, the invention has the advantages that the recognition capability of the earlier-stage risk of silencer development is improved, the originaldevelopment process depending on tests and repeated iteration is simplified, and the development cost and time are saved.

Description

technical field [0001] The invention relates to a method for calculating radiation noise of a muffler of an exhaust system, belonging to the technical field of engine exhaust systems. Background technique [0002] Traditional exhaust system muffler radiation noise control is generally as follows: through the modal analysis of the muffler shell in the early stage, the dynamic characteristics of the shell are understood, and the resonance caused by the excitation of the engine and air flow is avoided by increasing the modal frequency of the shell as much as possible. . In the later stage, the muffler sample is manufactured and installed on the prototype car for actual measurement. If the radiation noise is found to be large, the acoustic structure is changed again, and the sample is redone for testing again. [0003] Although the traditional exhaust system muffler radiation noise evaluation method can be developed normally, there are some obvious defects due to the lack of me...

AI Technical Summary

Problems solved by technology

[0004] Lack of pre-assessment methods, only the modal frequency can be used as an exact reference, except for very poor performance, it is generally difficult to detect the radiation noise problem of the muffler itself in the early stage;

[0005] The cost of later iterations is too high. Once the problem of radiation noise occurs, the structure needs to be readjusted, prototypes made, and tested again, and there is still a risk of failing the test. Repeated iterations are time and costly.

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