CN2240613Y - Silencer for internal combustion engine - Google Patents

Abstract

The utility model discloses a silencer for an internal combustion engine. The silencer for an internal combustion engine is particularly suitable for noise reduction work of high pulse airflow with air power and strong noise which are generated from medium and mini internal combustion engines. The silencer for an internal combustion engine is composed of a split air inflow expansion pipe 1, a buffering branch pipe 2, a buffering chamber 3, a pore 4, a partition plate 5, a chamber 6, an air outlet pipe 7, an expansion pipe 8, a casing 9, etc. An integrated structure for noise reduction with a multilevel expansion pipe is composed of the split air inflow expansion pipe 1, the buffering branch pipe 2, the buffering chamber 3, and the expansion pipe 8. The utility model relates to the silencer which has the advantages of small fluid resistance and strong capability for noise reduction.

Description

Internal combustion engine exhaust silencer

The utility model relates to a kind of internal combustion engine exhaust silencer, is the noise that a kind of internal-combustion engine is produced when exhaust, by the inner denoising structure of silencing apparatus, makes the silencer of noise attentuation, is specially adapted to the noise reduction work of medium and small combustion air power character noise.

Existing internal combustion engine exhaust silencer adopts the aperture denoising structure more, when the air power noise of internal-combustion engine is accompanied by pulsing airflow by the silencing apparatus inner aperture, makes noise attentuation, reaches the noise reduction purpose.Because medium and small I. C. engine exhaust pressure has certain limit, the silencing apparatus gas-flow resistance must be less than setting value, thereby the aperture and the percent opening of above-mentioned silencing apparatus noise elimination aperture are bigger, though resistance is little, noise reduction capability is poor, can not reach effective noise reduction purpose, if above-mentioned silencing apparatus small aperture and percent opening are reduced, gas-flow resistance is increased, and noise reduction may be quite a lot of, yet exhaust pressure rises, resistance is big, power loss increases.Because in, compact internal combustion engine mostly is single cylinder or twin-tub, the cylinder number is few, the combustion gas compression ratio is big, the exhaust pulses degree is more serious, the sound proof housing finite volume of above-mentioned silencing apparatus in addition, there is not the effect of buffer gas flow, to I. C. engine exhaust pressure is increased, noise reduction is undesirable, resistance is big, the technology and the economic performance of internal-combustion engine have been influenced, because above-mentioned silencing apparatus does not have the gas buffer structure, air-flow is in passing through the whole process of silencing apparatus, and air-flow is pulse, when the pulsing airflow instantaneous velocity is in peak value, instantaneous velocity is very big, and small structure can produce the secondary very noisy during to the high velocity air noise reduction.

The purpose of this utility model provides a kind of exhaust silencer that is suitable for internal-combustion engine, and its volume is little, in light weight; Raw material are economized, cost is low; Gas-flow resistance is little, anti-acoustic capability is good; Be specially adapted to the high impulse air-flow of medium and small internal-combustion engine generation and the noise reduction work of very noisy, have good technology capability and economic performance, to overcome above-mentioned the deficiencies in the prior art.

Task of the present utility model is to realize like this, it mainly is made up of flow deviding type air inlet expanding duct, housing, expanding duct, exhaust exit pipe, the inner chamber that it is characterized in that housing is divided into two or more several chambers by dividing plate vertically, first chamber is a buffer cell, flow deviding type air inlet expanding duct, buffer cell, buffering arm and expanding duct are formed the compages of a multistage expanding duct noise reduction, dividing plate is provided with expanding duct, at the exhaust outlet place, is provided with exhaust exit pipe.Part or all of flow deviding type air inlet expanding duct places in the buffer cell, its outlet is sealed, on near the tube wall the closed end, have several apertures, be positioned at buffer cell, on the tube wall of flow deviding type air inlet expanding duct, one or more several buffering arms and flow deviding type air inlet expanding duct are set communicate, flow deviding type air inlet expanding duct can be one or more.On the dividing plate of chamber expanding duct is set, the entrance point of expanding duct seals, and has several apertures near the tube wall its closed end, and expanding duct can be one or more.The exhaust exit pipe entrance point seals, and near the tube wall the closed end, has several apertures, and exhaust exit pipe can be one or more.Housing is the hybrid type housing of single hull or single hull and sound-absorption layer.

The fast-pulse air-flow that internal-combustion engine discharged, through muffler inlet, enter silencing apparatus flow deviding type air inlet expanding duct, through the outlet side of this pipe aperture, entering first chamber of silencing apparatus is buffer cell, because contraction and the expansion of sound wave when small holes makes noise produce attenuation of the first kind, increase along with the instantaneous velocity of pulsing airflow, partly air-flow directly enters buffer cell through the buffering arm on the flow deviding type air inlet expanding duct, to keep the basicly stable of flow deviding type air inlet expanding duct ingress pressure, sound wave is by the buffering arm time, owing to sound wave shrinks and expansion generation decay, by two part sound waves of aperture and arm, they are different with distance to the distance of buffer cell process in the buffer cell inner chamber, produced phase difference and acoustic interference, made the noise attenuation of the second kind.The expanding duct entrance point aperture of air-flow in buffer cell on dividing plate enters expanding duct, exports into second chamber from expanding duct, through the aperture of exhaust exit pipe entrance point, enter exhaust exit pipe discharging atmosphere after the expansion, in this flow process, sound wave has repeatedly shrinkage expansion, produces repeatedly decay.Gas from muffler inlet to the discharging, through the repeatedly expansion of sound wave, produce repeatedly noise reduction process, because through the gas of flow deviding type air inlet expanding duct behind the buffer cell is stable, there is not pulse, moment flow velocity through each grade expanding duct aperture is bordering on mean velocity, it is significantly less than the speed of pulsing airflow peak value, reduced the gas-flow resistance of silencing apparatus, eliminated the pulse of gas, the instantaneous velocity through small holes is descended greatly, improved the function of aperture noise reduction, prevented the pulse gas high-speed secondary very noisy that produces of the moment when peak value, adopted the compages of multistage expanding duct noise reduction, noise reduction capability is improved greatly.Therefore, the utility model has very strong noise reduction capability and very little gas-flow resistance to internal-combustion engine generation high impulse air-flow and microseismic noise.

Below in conjunction with accompanying drawing embodiment of the present utility model is described in further detail.

Accompanying drawing is a structural representation of the present utility model.

Among the figure, 1, flow deviding type air inlet expanding duct 2, buffering arm 3, buffer cell 4, aperture 5, dividing plate 6, chamber 7, exhaust exit pipe 8, expanding duct 9, housing.Silencing apparatus is single hull 9 formations of a hollow as shown in the figure, the centre is that a dividing plate 5 is separated into two chambers vertically, be buffer cell 3 and chamber 6, first chamber is a buffer cell 3, flow deviding type air inlet expanding duct 1, buffer cell 3, buffering arm 2 and expanding duct 8 are formed the compages of a multistage expanding duct noise reduction, two expanding ducts 8 are set on dividing plate 5,, are provided with exhaust exit pipe 7 at the exhaust outlet place.The part of flow deviding type air inlet expanding duct 1 places in the buffer cell 3, its outlet is sealed, on near the tube wall the closed end, have several apertures 4, be positioned on the tube wall of flow deviding type air inlet expanding duct 1 of buffer cell 3, be provided with two buffering arms 2 and flow deviding type air inlet expanding duct 1 and communicate.The entrance point of expanding duct 8 and exhaust exit pipe 7 seals, and near the tube wall the closed end, has several apertures 4.

When pulsing airflow and noise pour silencing apparatus buffer cell 3 through flow deviding type expanding duct 1 along aperture 4 from muffler inlet, because the shrinkage expansion of sound wave in passage, acoustic energy is decayed first, because the instantaneous velocity of pulsing airflow is in the increase of moment, air-flow is risen through the resistance drop of the aperture 4 of flow deviding type expanding duct 1, impel a part of air-flow to flow to buffer cell 3 from cushioning arm 2, stablize gaseous pressure thus and eliminated the suction pulsation phenomenon, at the sound wave of buffer cell 3 from buffering arm 2 and aperture 4, because the approach that they transmit is different with distance, caused phase difference, formed acoustic interference, noise is reduced for the second time.Air-flow and noise enter chamber 6 from buffer cell 3 after expanding duct 8 expansions, pass through exhaust outlet tube drainage atmosphere again, and gas and noise make noise produce decay again through repeatedly expansion, reach the noise reduction purpose at last.Therefore gas and noise enter from the flow deviding type air inlet expanding duct 1 of silencing apparatus, discharge from exhaust exit pipe 8 by the silencing apparatus internal structure, noise will be through repeatedly decay, because the utility model employing flow deviding type buffer method is the most suitable to the medium and small internal-combustion engine of single cylinder or twin-tub.It has eliminated the pulse of exhaust and gas-flow resistance and the secondary very noisy that pulsing airflow is produced when peak velocity.

Claims (5)

1, a kind of internal combustion engine exhaust silencer, mainly form by flow deviding type air inlet expanding duct, housing, expanding duct, exhaust exit pipe, the inner chamber that it is characterized in that housing (9) is divided into two or more several chambers by dividing plate vertically, first chamber is the compages that buffer cell (3) flow deviding type air inlet expanding duct (1), buffer cell (3), buffering arm (2) and expanding duct (8) are formed a multistage expanding duct noise reduction, dividing plate (5) is provided with expanding duct (8), at the exhaust outlet place, be provided with exhaust exit pipe (7).

2, by the described silencing apparatus of claim 1, part or all that it is characterized in that flow deviding type air inlet expanding duct (1) places in the buffer cell (3), its outlet is sealed, on near the tube wall the closed end, have several apertures (4), be positioned at buffer cell (3), on the tube wall of flow deviding type air inlet expanding duct (1), one or more several buffering arms (2) and flow deviding type air inlet expanding duct (1) are set communicate, flow deviding type air inlet expanding duct (1) can be one or more.

3, by the described silencing apparatus of claim 1, it is characterized in that the entrance point of expanding duct (8) seals, have several apertures (4) near the tube wall its closed end, expanding duct (8) can be one or more.

4, by the described silencing apparatus of claim 1, it is characterized in that exhaust exit pipe (7) entrance point seals, near the tube wall the closed end, have some apertures (4), exhaust exit pipe (7) can be one or more.

5,, it is characterized in that the hybrid type housing of housing (9) for single hull or single hull and sound-absorption layer by the described silencing apparatus of claim 1.