Double-frequency adjustable Helmholtz silencing cavity of vehicle engine

Abstract

The invention discloses a double-frequency adjustable Helmholtz silencing cavity of a vehicle engine. The double-frequency adjustable Helmholtz silencing cavity comprises a rotary sleeve mounted on the outer side of a hole penetration pipe in a sleeving mode and an outer pipe mounted on the outer side of the rotary sleeve in a sleeving mode and arranged eccentric to the rotary sleeve. An eccentricring cavity is formed between the rotary sleeve, the outer pipe, an outer pipe front end cover and a rear end cover. The middle portions of the hole penetration pipe and the rotary sleeve are provided with corresponding holes. The outer circumferential surface of the rotary sleeve is provided with two blade grooves. The blade grooves extend to the two ends of the rotary sleeve in the axial direction. An expansion blade is arranged in each blade groove. An included angle theta is formed between the two expansion blades. The eccentric ring cavity is divided into an acute-angle ring cavity and an obtuse-angle ring cavity through the two expansion blades. A volume adjusting device is connected with the rotary sleeve. According to the double-frequency adjustable Helmholtz silencing cavity, therotary sleeve is driven to rotate through the volume adjusting device to change the sizes of the acute-angle ring cavity and the obtuse-angle ring cavity so as to achieve the noise elimination frequency adjustability of a silencer. The double-frequency adjustable Helmholtz silencing cavity of the vehicle engine is simple in structure, quick in response and wide in covering working condition, andthe inertia of the volume adjusting structure is small.

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...

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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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