this ppt is all about that how to control the noice in ic engines

1. Noise Control in IC Engine
Prepared by: Baradananda
jena

2. OVERVIEW
• Introduction
• Internal Combustion Engine Noise
• AERODYNAMIC NOISE
• COMBUSTION NOISE
• MECHANICAL NOISE
• EXHAUST SYSTEM NOISE
• INTAKE SYSTEM NOISE
• COOLING SYSTEM NOISE
• Water Cooled Engines
• Remedial Measures

3. Introduction
• Noise control is becoming increasingly important for a wide variety of
OEM designers. Examples of products that take noise control
considerations into account during their design cycles include equipment
such as computer hard drives, house appliances, material handling and
transportation equipment etc.

4. Internal Combustion Engine Noise
One typical engine noise classification technique separates the
aerodynamic noise, combustion noise and mechanical noise.
• AERODYNAMIC NOISE
• COMBUSTION NOISE
• MECHANICAL NOISE

5. AERODYNAMIC NOISE
• aerodynamic noise includes exhaust gas and intake air noise as well as noise
generated by cooling fans, auxillary fans or any other air flow.

6. COMBUSTION NOISE
• combustion noise refers to noise generated by the vibrating surfaces of the
engine structure, engine components and engine accessories after
excitation by combustion forces.

7. MECHANICAL NOISE
• mechanical noise refers to noise generated by the vibrating surfaces of the
engine components and engine accessories after excitation by reciprocating
or rotating engine components.

8. INTAKE SYSTEM NOISE
• Intake system noise includes noise generated by the flow of air
through the systems air inlet and noise emitted from the
vibrating surface components. As with exhaust systems surface
radiated noise results from two different types of excitation
process: those generated by the pulsating intake air flow and
those transmitted from the vibrating engine to intake system
components. In many instances, an engines air cleaner will
provide significant attenuation of intake air noise. If additional
attenuation is required, an intake air silencer can be added to the
system. To minimize intake system surface radiated noise,
proper design, selection and mounting of intake system
components are essential.

9. EXHAUST SYSTEM NOISE
• Exhaust system noise includes the noise from exhaust gas pulses
leaves the muffler or tail pipe and noise emitted from the
vibrating surfaces of the exhaust system components. Noise
emitted from the surfaces of exhaust system components results
from two different types of excitation forces: those generated by
the pulsating exhaust gas flow and those transmitted from the
vibrating engine to exhaust system components. Additional
considerations in the reduction of exhaust system noise include
proper selection of piping lengths and diameters, proper
mounting of exhaust system components and proper positioning
of the exhaust outlet.

10. COOLING SYSTEM NOISE
• Water cooled engines are typically cooled by using a radiator as a heat
exchanger – with an axial flow fan is used to draw cooling air through
the radiator. Air-cooled engines generally use a centrifugal fan in
conjunction with shrouding to direct cooling air across the engine. Fan
noise consists of both discrete frequency tones and broadband noise.
The broadband components of fan noise are caused by the shedding of
vortices from the rotating fan blades and by turbulence in the fans air
stream.

11. Water Cooled Engines
• A variety of design parameter affect at the sound-emission levels of
axial-flow fans, but fan blade tip speed is the dominant factor. To
minimize fan tip speed, while still providing sufficient engine cooling,
the cooling system’s efficiency must be as high as possible. To maxmise
cooling system efficiency in water-cooled engines, the following
consideration should be made-
• 1. use water pump and radiator that have adequate capacities,
furthermore, be sure that the radiator core has sufficient surface and air
flow areas.
• 2. use a fan with proper aerodynamic blade design.
• 3. use a shroud to prevent recalculation of air from the high pressure side
of the fan in the low pressure side. Clearance between the tips of the fan

12. Remedial Measures
1.Stopping it at the source:
• Improving the engineering in many noisy objects has cut noise nearly by
30 decibels (i.e. snow mobiles).
• Government has set up regulations to manufacturers such as GM and
Mack truck to reduce vibration in heavy gears, axles and transmissions.
• Reducing sound at the sources by an average of 10 decibel cuts soundness
in half.

13. Remedial Measures
• MECHANICAL DESIGN OPTIONS:
• Glass Pack
• Low Flow Restriction
• Low Noise Attenuation
• Unpacked Concentric Tube Resonators
• Single-pass
• Multi-pass
• Passive

14. Design 1: Single-pass
Holes in pipe
Resonating
Chamber
Inner Pipe
Exhaust Gas
Flow
Sound Waves

15. Design 2: Multi-pass
Exhaust Gas
Flow
Resonating Chamber
Exhaust Gas
Flow

16. •Passive:

17. Designs 3 : Metal Foams
www.bundesregierung.de

18. Optimal Foam Structure
Industrial Noise Control Handbook. Cheremisinoff and
Cheremisinoff

19. Absorption Area
Industrial Noise Control Handbook. Cheremisinoff and
Cheremisinoff

20. Design 4: Exhaust Silencer Insert
• Applied to exhaust tip
• Reflects Sound Waves back into
exhaust stream

21. Design 5: Active Single-pass
Resonating Chamber
Frequency Data
Moves laterally
Exhaust Gas
Flow

22. Design 6: Active Multi-pass
Resonating Chamber
Frequency Data
Moves laterally
Exhaust Gas
Flow

23. 2. SHIELDING YOUR EARS
• Without doubt, plugging up your ears is the cheapest and easiest
method of noise control.
• If you have to be around loud noise protecting yourself with earplugs
is better than doing.
• Excessive exposure to loud noise and or exposure to a quick sound
noise could cause serious damage to your ears.

24. Conclusion
Interest in noise and its reduction pass become wide spread
in many industrial advanced countries. Noise standards and
legislations exists in such countries for protecting urban
residents and industrial workers from hazards caused by
excessive noise levels. It is high time that we also start
thinking of such steps before the noise problem becomes
too large and unwieldy. In mean while, as engineers we
should try to control noise to the extend possible by
properly designing machines and appliances by suitably
locating machines and office space in industry by judicial
location of presidential areas and high ways by using
proper noise control methods to reduce existing noise
problems.

25. Reference
•Noise cancellation systems by Jeffery .N Denenberg.
•A study of noise reduction method on motorcycle- SAE
1999-01-3257 JSAE 9938012
•Design strategies for low noise engine concepts by F.K
Brandl, P.Wunsche
•Noise control in IC engines – BAXA
•Diesel engine reference book- Bernard Challen