NOISE REDUCTION METHOD ON MOTORCYCLES

By: RAMEES.M

CONTENT

INTRODUCTIONEXHAUST SYSTEMHOW IT WORKSMUFFLERTYPES OF MUFFLERWORKINGEXHAUST QUIETING METHODSCONCLUSIONREFERENCE

INTRODUCTION

. In reality sound of the motor bike gets controlled by the exhaust mechanism of the vehicle.The muffler present in the vehicle also reduces the noise to a greater extent.Poorly designed mufflers can result in a considerable power loss.the aim is to get the maximum power and reduced noiseMufflers get installed within the exhaust arrangement of modern I.C engines

EXHAUST SYSTEM Main parts:

Exhaust manifold

Catalytic converter

Oxygen sensor

Exhaust pipe

Muffler

How it works

Exhaust manifold: It’s connect to the engine. Take all cylinders exhaust to one pipe. Made from steel, stainless steel or aluminum.

Catalytic converter:This muffler changes harmful carbon and hydrocarbons to water stem and carbon dioxide.

Oxygen sensor:It’s measure how much oxygen in the exhaust. It’s connect to computer to control the correct mixture for fuel economy.

Muffler:It’s work to reduce the noise of the exhaust process .

Exhaust pipe:It’s work as connect all parts together and move the gas throw it .

MUFFLER :To reduce the noise, the engine exhaust is connected via exhaust pipe to the silencer. A tail pipe carries the exhaust gases from the muffler to the rear or side of the vehicle near the wheel.The noise consist of different notes of various frequencies. The any silencer for absorbing this noise must effectively reduce both the low and high frequency noise. In some designs, the muffler has several resonators of different sizes to target a range of frequencies

TYPES OF MUFFLER1. BAFFLE TYPE It is generally cylindrical in shape with a number of

baffles spot welded inside. Major drawback of the mufflers is their low efficiency.

Because of the restriction provided to the flow by the baffles, the back pressure is increased, thus causing in loss in engine power.

2.WAVE CANCELLATION TYPEIn this type, exhaust gases are divided into

two parts.In practice this type of muffler does not

eliminate noise completely, because this is only at one frequency for which muffler is designed, where as noise is a combination of different frequencies

3.RESONANCE TYPEThese are also called helmhotlz type, after the

person who originated this idea. It consist of a number of helmhotlz resonator

in series, through which a pipe containing access ports passes.

Series of resonators eliminate the fundamental and harmonics of the engine noise.

4.ABSORBER TYPEThe sound absorbing material, usually fibre

glass, is placed in this case around the perforated tube through which the exhaust gases pass.

During high pressure fluctuations the gases pass through the perforations to the sound absorbing material, when these fluctuations are reduced and thus the noise gets reduced in intensity.

5.COMBINED RESONANCE TYPEIt is seen that the absorber type muffler, has

a drawback in that it is not efficient in reducing noise of low frequency.

To obviate this defect, this is combined with a resonant chamber.

This type is more efficient than either the simple resonance or the absorber types.

WORKING

oAs gas burns inside the engine, fumes and exhaust gases flow through the exhaust pipe and pass through one or a small series of tubes. From there, they pass through the catalytic converter. oIn the converter, harmful substances such as Carbon Monoxide (CO) which causes green house effect are broken down before they are released into the atmosphere. othe muffler resonates, it decreases some of the engine noise before allowing the gases to exit through the end of the muffler

CONCLUSION

One of the easiest ways to quiet the bike’s exhaust is to switch back to the factory-installed mufflers and pipes.. Other methods involve purchasing mufflers with special features like resonators, baffles or materials like fibre glass.Motorcycles straight from the factory are the most likely to be quiet, as manufacturers comply with sound restrictions in different countries.

REFERENCE

WWW.wikipedia.Automobile engineering-volume 2 (Dr. kirpal singh ). AMA (American Motorcyclists Association). 2009.Exhaust System Sound Emissions Ordinance. Pickerington, OH.

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