A dual-frequency adjustable Helmholtz muffler cavity for a vehicle engine

Abstract

The invention discloses a dual-frequency adjustable Helmholtz muffler cavity for a vehicle engine, which comprises a rotating sleeve sleeved on the outside of a perforated tube, an outer tube sleeved on the outside of the rotating sleeve and arranged eccentrically with the rotating sleeve, An eccentric annular cavity is formed between the rotating sleeve, the outer tube, the front end cover and the rear end cover of the outer tube; the perforated tube and the middle part of the rotating sleeve are provided with corresponding holes, and the outer surface of the rotating sleeve is provided with two vane grooves. The groove extends to both ends of the rotating sleeve in the axial direction. Each blade groove is provided with a telescopic blade, and the angle θ is formed between the two telescopic blades. The eccentric annular cavity is divided into an acute angle annular cavity and an obtuse angle by the two telescopic blades. The annular chamber and the volume adjusting device are connected with the rotating sleeve, and the volume adjusting device drives the rotating sleeve to rotate, changing the size of the acute-angled annular chamber and the obtuse-angled annular chamber to realize the adjustable muffler frequency. The invention has the advantages of simple structure, small inertia of the volume adjustment structure, fast response and wide coverage of working conditions.

Description

technical field [0001] The invention relates to a noise reduction device, in particular to a dual-frequency adjustable Helmholtz noise reduction chamber suitable for vehicle engines. Background technique [0002] As a typical structure of micro-perforated plate noise reduction, perforated pipe is widely used in vehicle intake and exhaust systems, but its fixed volume and definite perforation rate can only play a major role in noise reduction for a specific frequency band, that is, it is suitable for The speed and load conditions are limited. [0003] Chinese patent CN103486394A is a frequency-adjustable micro-perforated tube muffler with a variable perforated section length. It is mainly based on the rotating speed of the rotating machine, based on the adjustable perforated tube length, and at the same time adjusts the axial resonance volume to realize the adjustable muffler frequency. , whose frequency variation is not linear. When the required volume is small, the struct...

AI Technical Summary

Problems solved by technology

When the required volume is small, the structure has a waste of space; when the speed change range is large and the speed change frequency is high, that is, the required volume change rate is large, the transient response characteristics of the axial motion caused by the reciprocating inertia of the structure are poor

At the same time, the motor controller only adjusts the frequency based on the speed signal, and there are limitations. When the engine speed is constant and the load is different, the frequency of the noise peak is not consistent.

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