Automotive Pollution Control

8/16/2019 Automotive Pollution Control

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NOISE POLLUTION


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Noise

Undesirable or

unwanted

sound

Impacts

,

Stress

ys ca

an

psyc o og ca

amage


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Noise Pollution Causes

Noise From

Automobile

‐‐‐‐‐‐‐‐very

high

Railway Stations

ircrafts

Industrial Noise Construction Equipment

Household Equipment

Other Causes


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Road Traffic Noise

• Traffic is the biggest source of noise pollution in

to ays t mes, espec a y n ur an areas.

• In the past few years the number of automobile

vehicles has increased manifold.

• us, ra c pro ems crea e y ese ve c es s an

important source of noise pollution.

• The sound produced by the exhaust systems of trucks,

, , , . .


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Noise Generation

Road Traffic

noise

is

the

aggregation

of

noise from individual vehicles in the traffic stream.

Th r

r

v n

rin i l

f r

n

which the generation of road traffic noise de ends:


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….CONTINUED….

• Traffic volume

•

• Traffic composition

• oa gra en

• Road pavement surface type and texture

• Driving conditions

• Individual vehicle noise


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7


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8http://www.nonoise.org/library/highway/traffic/traffic.h


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9http://www.nonoise.org/library/highway/traffic/traffic.h


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• The

engine• The transmission

• The braking system

• The interaction

of

tyres and

road

pavement

surface

• Body, tray and load rattles

• Movement of air around the vehicle

• Horn


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Noise From Engine

There could be several reasons that could be causing a

.

engine is not being completely lubricated.

s wou e cause y e er e eng ne ac ng o , or

the engine not having sufficient oil pressure.

Engine Noise Remedy

..Use professional quality oil filters.

.. By using Spark Plug Threads


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D namat under the hood

Dynamat - Expensive material but very very effective,

most eo le use this material for car audio because it

works really good to improve sound and stop vibrations and

rattling.

Dynamat -will protect the hood's paint finish from engine

heat to the engine as well.


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Noise reduction in two wheeler gears

Gear noise can be attributed to several reasons such as

gear design parameters, gear material used etc.

Owing to design, spur gears during operation produce

noise

A change in gear design to helical would reduce the noise,but at in the cost of an increase in friction as in operation it

produces an axial thrust.

A more economic and effective way of noise reduction ingears would be to go in for a material, which has good

significantly.


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cont….

A new member of the cast iron family, Austempered Ductile Iron

(ADI), is a heat treated Spheroidal Graphite Iron(SGI).

The microstructure exhibits ausferritic structure with a high

volume of carbon-enriched austenite and nodular graphite.

This offers the gear designer a combination of manufacturing

flexibil ity, high strength, toughness, low weight, excellent fatigue

strength and wear resistance.

These properties are present along with good damping capacity

and machinability.

. ADI thus developed has been evaluated for mechanical

properties like tensile strength, impact strength etc.,..

ADI possess significant damping properties and helps in gear

noise reduction.


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TYRE NOISE

THE

TYRE

HITTING

THE

GROUND…

THE VIBRATION OF THE AIR THROUGH THE

THREAD

PATTERN…

THE VIBRATION PASSING THROUGH THE TYRE..

NOISE DEPENDS ON THE ROAD SURFACE AND ……


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The noise which is radiated from the tyre surface is produced by several mechanisms, including the vibration of the tyre

,

road surface


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Surface texture bum s and di s

Avoid (flatten) texture that repeats itself at intervals of 1 inch or larger.

. ., ,

fine texture (that is on the scale of 1/8 to 1/4 inch) should be provided.

Texture should be “negatively” oriented, meaning that any “deep” texture

should point down (e.g., grooves) rather than up (e.g., fins).

Joints, ,

also annoyance.

-

Faulted joints should be avoided by providing adequate load transfer.


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The exhaust system of an internal combustion engine has anumber of functions, one of which is to reduce the noise of the

atmosphere

The three basic exhaust noise mechanisms are:• - s s e no se ra a e rom e uc as opensinto the atmosphere

• -mounting system to the surrounding structure.

• - the exhaust system (pipes, catalysts and silencers).


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Noise POSSIBLE PROBLEM SOLUTIONBACKFIRING S Incorrect ignition timing, faulty ignition or

leaking valves

Have ignition and/or valves checked.

CLATTER FROM ENGINE Insufficient engine oil.Worn or badly adjusted valves.

Add oil.Refer to a mechanic

WHINING OR CHATTERING FROMENGINE

Incorrectly tensioned camshaft drive belt. Refer to a mechanic as soon as possible

RATTLE WHEN ACCELERATING Wrong grade of fuel;

engine overheating;engine needs decoke

incorrect ignition timing;i nition s stem fault.

Use higher grade of fuel;

Refer to a mechanic.

KNOCKING FROM ENGINE WHICHINCREASES WITH ENGINE SPEED

Worn camshaft or cam followers. Refer to a mechanic as soon as possible.

SCREECH UNDER ACCELERATION Slipping auxiliary drive belt/fan belt. Check/adjust belt or have a replacementfitted.

SCREECH WHEN STEERING Power steering belt slipping. Check/adjust belt.

STEERING

. .

ROAR OR RASP UNDER ACCELERATION

Blown exhaust. Have exhaust checked.

SQUEAL OR GROAN WHEN BRAKING Worn or defective brake com onents. Refer to a mechanic.

HISS FROM ENGINE Leak from coolant or air/vacuum hoses. Refer to a mechanic.

CLICKING FROM WHEELS Loose hubcap; Tighten hubcap;


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NOISE (vs) SPEED


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How To Measure

The

Noise….???

dB:

What

is

a

decibel?

Intensity of a single sound is measured on a relative of

logarithmic

scale Uses a unit ca e a e B or su unit – eci e B,

1/10 of a bel)

,


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S.NO Type of vehicle Noise Limits from 1st

Date of implementation

January, 2003,

dB(A)

1 Two wheeler

Displacement upto 80

cm3 75

than 80 cm3 but upto 175 cm3

Displacement more

80 Ist January,2003

than 175 cm3

2 Three wheeler sp acemen up o 175

cm3 Displacement more than 17 cm

77

80 Ist January,2003

3 Passenger

car 75 Ist January,2003


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e eve o ommon oun s

Source Noise Level (dB) Effect

arr er ec e opera on, a r ra s ren a n u y ou

Jet takeoff at 200 feet 130

Disco, thunderclap 120 Maximum Vocal Effort

Auto Horn at 3 feet 110

Garbage Truck 100 , , -

Alarm Clock at 2 feet, hair dryer 80 Annoying

Noise restaurant, freeway traffic, persons voice at 3 feet 70 telephone use difficult

Air conditioning unit at 20 feet 60 Intrusive

Light auto traffic at 100 feet 50 quiet

, ,

Library, soft whisper at 15 feet 30 very quiet10 Sound just audible

0 Hearing begins


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um er o peop e annoye


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….CONTINUED….

Significant

variability

in

noises

from

transportation sources

A

‐ weighted

noise

level

(equivalent

“irritation”

level – has to do with mix of frequencies)

DNL (day/night

level

– weights

night

time

noises)


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Noise Propagation Noise is generated at source and spreads spherically away

from source

n ens y m n s es w s ance

Losses also occur from sound energy being dissipated as

sound is

transferred

b

air

articles

Bending and diffraction occurs as sound waves encounter natural and manufactured solid objects


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Road Traffic Noise propagation

Propagation

is

the

wave

process

where

There

are

a

number

of

factors

which

n uence e propaga on o roa traffic as follows:


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….CONTINUED….

Road

corridor

cross

sectionDistance between source and reception po nt

Type

of

intervening

ground

cover

between

. , water or concrete)

obstructions


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Control of Transportation Noise

Federal ‐‐

Noise

control

act

of

1972 Reco nized noise as a ma or de rader of urban

living

Encourage use

of

noise

standards

State and local governments


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Noise Control Strategies

Source

controls Vehicle control devices – maintenance, traffic

an ig way esign contro s

Path

controls Sound barriers that reflect and diffuse noise

Buffer zones

Receiver‐si e

contro s

Insulation

31


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Traffic Control Measures

Prohibit

trucks

ruc rou es

Prohibit

daytime

(or

night

‐time)

use

Traffic signal timing..

pee

imits

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SOURCES OF ENGINE NOISEEngine noise is the sum of two elements:1. com ust on no se

2. mechanical noise.

• mechanical noise dominates the engine noise produced by

spark ignition (gasoline) engines;

• combustion noise is a more significant contributor to the engine

noise produced by compression ignition (diesel) engines.


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Combustion noise.

applied to the structure of the engine, causing vibration to occurwhich is then radiated as noise

2.The gas forces in each cylinder vary during the working

cycle of the engine (two or four stroke). They are highestduring the combustion period where the cylinder pressure

rising quickly.


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Mechanical noise1. The crank mechanism(pistons,connecting rods,crankshaft,

bearings) experiences externally applied forces due to gas

forces and internally generated forces

2. Around TDC there is a rapid reversal in side force produced

by the slider-crank mechanism. This produces piston slap as the p s on mpac s on e cy n er- ner. s on s ap s norma y e

dominant source of mechanical noise in the diesel engine.

3. Piston slap noise increases with engine speed. It also increaseswith turbo charging. It is mostly controlled by reducing

-


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Mechanical noise1. In gasoline engines, piston/liner clearances are relatively

small, and mechanical noise tends to be dominated by impactsin the crankshaft bearin s made throu h the oil film.

2. At low engine speeds these are magnified by increasing

. ,

crank mechanism dominate so there is little load dependency.


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Mechanical noiseOther sources of mechanical noise include:

• timing drive;• valve train

• fuel injection equipment.


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Measurement of engine noise• ,

acoustically treated test cell that replicates the outdoor environment(commonly a semi-anechoic cell with large sound absorbing wedges

on e wa s an ce ng an a a concre e oor .

• The engine is either tested in its bare state (with just enough

equipment to run – pumps and manifolds are fitted but theintake/exhaust noise is ducted away) or in its fully equipped state

(everything fitted including ancillaries and sometimes full intake and

.

• The engine is tested at the maximum power point, at the maximumtorque point, at the point of maximum speed but minimum load and

a so a e.


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Measurement of engine noise• oun pressure eve s are measure a ree pos ons or eac

engine operating condition. These are at 1.0m from the longitudinalcentres of the vertical planes forming the smallest rectangular box

which completely encloses the bare engine. The measuring points

are on both sides and in front of the engine at the height of the

• The noise levels at the three specified locations are reported.


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Measurement of engine noise‘ ’ -

same height and distance from the box as the specified locations. Ifthe survey reveals readings more than 3 dB

above the highest reading at the specified locations, then the

survey readings are also reported.

• The reported results should be the averaged results of two or

more test results within 2 dB of each other.


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Engine noise control1. The period between the start of the injection and ignition, known

as ignition delay period has an important Learning on combustion

noise. Turbo charging, by which air is forced into the intake at

,

period and a more gradual rise in pressure with, consequently, lower

noise generation.


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Engine noise control• stiffen structures to ush resonant fre uencies above the

highest forcing frequency;

• encapsulate noise sources with massive panels;

• add damping where resonances occur.


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Engine noise control• Oil pan – the use of an isolating gasket between the oil pan andt e cran case. e a opt on o structura a um n um o pans to

replace the traditional pressed steel components has made oilan noise more si nificant in s ite of im rovements to the

crankcase to reduce its noise radiation.

• –

• Fuel injection equipment – the adoption of common rail

systems an un t n ector systems w c are more compact an

quieter have brought about significant improvements


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Engine noise control• Intake s stem – the avoidance of lar e lanar surfaces on intake

components can reduce noise emissions along with general stiffening

of the structures.

• Noise shields – well-damped, isolated engine covers can reduce

noise radiated by the engine structure.

• Engine bay enclosures – engines may be effectively enclosed within

their en ine ba in the vehicle thus enca sulatin the noise sources.

Problems with ventilation and cooling are common.

•


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Engine noise control

- ,use this material for car audio because it works really good to

improve sound and stop vibrations and rattling. To help this

re uce car eng ne no se ras ca y you wou wan o app y s

material to the bottom of the car hood and the firewall area of

the vehicle. You could also apply this material to the doors or

other areas of the vehicle. Dynamat will protect the hood's paint

finish from engine heat to the engine as well.


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Engine noise control1. Engine noise through the radio - From revving the engine or

just constant noise. Engine noise through your speakers is

- .

thing you could do is take all the grounding cables in vehicle

and put them one spot that is groundable2. Because of the difficulty, there is an additional option; buying

a Ground Loop Isolator which will eliminate the electrical

noise and hum caused b round loo s. This noise could also

be caused by running audio cables close together in thevehicle and components such as an amp, satellite radio, mp3

p ayer.

TRANSMISSION NOISE INCLUDES


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TRANSMISSION NOISE INCLUDES

GEAR BOX NOISE

CLUTCH NOISE

PROPELLOR SHAFT

NOISE

BEARINGS NOISE


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GEAR BOX

NOISE

S ur ear roduce more noise

Helical ears roduce less noise

S nchromesh

ear box

roduce

ver

less

noise


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impetus

for

the

most

noise

within

a

gear

box.Noise level and frequency are affected by:

Type of gear teeth

Gear tooth geometry

u r ca on


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Gear Tooth Selection

The more constant and uniform the contact, the lower the friction forces which cause noise

This is true for all types of gear designs: spur, e ical, spiral bevel or straight bevel.

Gear Tooth Geometry


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Gear Tooth Geometry

For example, increasing the height of a tooth to achieve reater overla or mesh can actuall reduce the ear's

ability to transmit load.

, near the tip of the gear tooth, can ease an incoming tooth

into

contact

with

other

teeth

This involves reducing the material on either end of a gear tooth to produce a more oval tooth profile.


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Smooth Finished

Surfaces

Normally, the

finer

the

finish,

the

lower

the

noise

level.


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Thicker Lubricants

While higher

viscosity

oils

and

greases

can

cut

down

on

noise


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Clutch noise

Do clutch noise is more

Friction clutch noise is less

Torque converters noise will be very less


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Definition

Devices which are used to reduce the sound levels

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Classification

Dissipative type

Combination type

Spark arresting type

Catalytic silencer

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Dissipative Type

Uses sound absorbing materials

Take energy out of acoustic motion in the

wave as it propagates through the silencer

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Reflects sound wave back to the source and prevent sound from

being transmitted along the pipe

Commonly used in automobile applications

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Expansion chamber type

change in cross sectional area in the pipe.

Do not have the high attenuation of the Hemholtz resonator, but have

a broadband frequency characteristic

Their performance also deteriorates at higher frequencies when the

Some expansion chamber muffler systems are also packed with sound

absorbing material which helps to improve the high frequency

a enua on.

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Silencer selection factors

Acoustical performance(insertion losses)

Aerodynamic performance(maximum acceptable pressure drop)

Mechanical performance

Material selection

Durability

Little maintenance

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Design factors

nser on osses

RestrictionVolume

Weight

Durability

Cost

Ease of manufacture

Styling

Tonal quality

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ome um ru es or es gn

Volume – 5-10 times en ine swe t volume

Tailpipe length – less than 500mm

>500Hz noise control – pack silencers with porous

materials such as basalt or glass wool

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Definitions

Noise

Noise is

defined

as

unwanted

sound

transmitted through air or another medium

Sound

It is defined as any pressure variation

(in air, water or some other medium) that

the human ear can detect

Sound Level Comparisons


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Measuring of

noise

dB: What is a decibel?

• The decibel (dB) is used to measure sound level..

• The dB is a logarithmic unit used to describe a ratio., The ratio may be power, sound pressure, voltage or

.,

to the

phon

and

the

sone (units

related

to

loudness).


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Causes of

noise

pollution

Traffic (Automobile)

Railway Stations

ircrafts

Industrial Noise

Construction Equipment

Household Equipment

Other Causes


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Definition of

traffic

noise

Road traffic noise is what you hear from driver's

vehicles, planes,

trains

and

buses

during

the

Examples of road traffic noiseSounds of engines speeding up,

horns blowing,

potholes being

hit

or

even

trucks

with

heavy

moving freight making lots of noise

Road Traffic Noise


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Traffic is the biggest source of noise pollution in

to ays t mes, espec a y n ur an areas.

In the past few years the number of automobile

vehicles has increased manifold.

us,

ra c pro ems

crea e

y

ese

ve c es

s an

important source of noise pollution.


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Sources of traffic noise in highways:

Automobiles

Buses

Motorcycles

Medium & Heavy Trucks


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u

sources o

no se

Tire Noise

Important for

autos

May be important for trucks

Tir ‐

P v m n

in r i nExhaust Noise

Low‐frequency

“rumble”


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Reasons for Traffic Congestion

Increase in car ownershipIncreased

commutin

Car ownership since 1920

YEAR NO.

OF

CARS

MILLIONS1920 O.51940 2.519 0 11

1980 191 0 21


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Problems caused by Commuting

Traffic Congestion

Air pollution

Noise pollution

Visual pollution

Parking problems

Destruction of houses

Increased risk of accidents

Factors Influencing of traffic Noise


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Generation • Road Traffic noise is the aggregation of noise from

v v .

• There

are

seven

principle

factors

upon

which

the

eneration of road traffic noise de ends:

1. Traffic volume

2. Average traffic speed

3. Traffic composition

4. Road gradient

5. oa pavemen sur ace ype an ex ure

6. Driving conditions

.


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Traffic Noise

Depends on vehicle mix

ou as

One heavy truck at 55 mph sounds as loud as

28 cars at 55 mph


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• De ends on vehicle s eed

– Tire/pavement noise dominates above 30 mph

Traffic at 65 mph sounds 2x as loud as

traffic at 30 mph


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Traffic Noise• Depends on amount of traffic

• Double

traffic

volume

=

increase

noise

by

3

dBA

+

= +3 dBA


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Tra c No se:

Trave

Patterns


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Solutions to Traffic problems

Widening roads

Bypasses

‐ inner ring roads

‐ outer ring roads

Urban Motorways

Bus lanes

Improving public transport

one way streets

Increase cost o car par ing


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Widening roads

B


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Bypasses

BournemouthRoad

High Street

Shrubbs Hill Road

t t


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one way streets

MDT N i P li


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MDT Noise PolicyMDT will consider installing noise berms or walls to

mitigate traffic

noise

IF:

6 noise re uction can e ac ieve

Affected landowners generally support mitigation

osts meet

a

ost‐

ect ve

n ex

Can be safely and reasonably built & maintained

N i B i


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Noise Barriers

Must block line of sight to vehicles on road

Will REDUCE

traffic

noise,

not

ELIMINATE

it

N i B i


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Noise Barriers

• REDUCE Noise, do not ELIMINATE

Noise

• Feasibility – safety, engineering factors, effectiveness

o wa

• Reasonableness ‐ overall benefits of abatement, public in ut.

• Mitigation cannot

protect

2

nd

floor• Decision to provide noise abatement made ONCE.

Mitigation Barriers


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Mitigation - Barriers

Mitigation Berms


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Mitigation - Berms

Mitigation Berm/wall


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Mitigation – Berm/wall

Mitigation Wall


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Mitigation – Wall

Noise Propagation


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Noise Propagation

Noise is generated at source and spreads spherically away

from source

n ens y m n s es w s ance

Losses also occur from sound energy being dissipated as sound is transferred b air articles

Bending and diffraction occurs as sound waves encounter natural and manufactured solid objects

Examples of road traffic noise


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Examples of

road

traffic

noise.

Road traffic noise is what you hear from driver's

vehicles, planes,

trains

and

buses

during

the

. , horns blowing, potholes being hit or even trucks with heav movin frei ht makin lots of noise are all examples of road traffic noise.


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The engine

The transmission

The braking system

The interaction of tyres and road pavement surface

Body, tray

and

load

rattles

Movement of air around the vehicle

Horn

NOISE REDUCTION TECHNIQUES


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NOISE REDUCTION

TECHNIQUES

Noise Reduction


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Noise Reduction

T ere is an increase sensitivity towar noise, rom a personal standpoint and a societal standpoint.

From front

and

side

windshields,

to

tire

wells

and

the

, unexplored when it comes to finding new ways to ensure a quieter driving experience.

There are increasin links between noise and vibration and at gue

e ort

are

ma e

n t e

c aracter st cs

n t e

development of the vehicle to minimize the noise and vibration harshness.

' vibration control components that are intended to reduce both

vibration

and

the

noises

created

by

the

vibration

within the vehicle.

Cont…

Cooper Standard's goal,is to isolate the engine from the restf th hi l


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p

g

g of the vehicle.

. as a solution for quieting the passenger compartment.

Their main

aim

is

not

trying

to

absorb

noise

once

it's

inside

, Carcoustics offers acoustics throughout the entire vehicle,

including the engine compartment, the interior and the

.Exploring the wheel wells and the body board for

additional noise reduction within the passenger

At

the

wheel

well,

Carcoustics has

added

an

acoustical

feature to

the

wheelhouse

liner.

‐ . .

systems


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systems

in the U.S. you have more or less injection molded, non‐

acoustical wheel

house

liners.

n urope, a same w ee ouse ner, an s o Carcoustics, adds acoustical features that reduce road tire noise, water spray noise in rainy weather and also reduces

noise from

stones

and

other

debris

coming

up.

Carcoustics acoustical wheel well is being used in the U.S .

Dashboard vents


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Dashboard vents

vents are the loudest points in an automobile

Carcoustics produced absorption

function

on

the

way

e ween e ven an e n er or o e ve c e o preven the noise from entering the vehicle

Glass


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Glasslaminate glass as one of the major trends in noise reduction.

swap

out

the

side

glass,

change

the

windshield

and

get

six

decibels of

noise

reduction.

Buick Rainier, Lincoln Navigator, Lincoln Aviator and the ultra luxury packaged Lexus LS430 all offer laminated glass

chan e from tem ered to laminated lass, ou et a significant

reduction

in

noise

because

in

the

past,

the

windshield was always the weakest link of where the sound was pouring into the interior.

An added benefit to laminated glass is weight reduction.


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Cont…

Solutia

Inc

offered

laminated

glass

product

called

VancevaQuiet's which has weight reduction capabilities.


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Dow Automotive offers a variet of roducts and services that target interior noise reduction. New to the U.S. this

year is the company's BetaMate, an adhesive that has been used

for

body

stiffness

improvements

and

stiffness

ura y w c equa es o v ra on re uc on.North America company LMS International provides the

software tools needed to make noise and vibration

possible. company's noise and vibration tools are

oun ua y,

Sysnoise and

LMS Test.Lab

Cont…


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Cont…LMS Sound Quality helps to subjectively identify, isolate

and rank the individual sounds that comprise a troublesome

noise.

Sysnoise predicts sound waves and the structural vibration induced by fluid loading effects onto a structure. The

pressure and radiated sound power, acoustic velocities and intensities, contributions of panel groups to the sound,

‐, , modes and structural deflections.

LMS Test.Lab is a dedicated measurement solution for .

Cont…


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Cont…In Porsche 944 engine The engine noise level was lowered

by primary

measures,

by

modification

of

the

solid

‐born

, neutralization. Particularly efficient were modifications to the crank gear, crankcase, valve gear, oil sump, intake

mani o , a ternator,

an

toot e

e t

rive

‐ ‐

Component Development


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Component Development

New blow moulding technology to reduce same level of

noise

reduction

but

lighter

in

weight.


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ENCAPSULATION


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Acoustic absorbers attached to the parts where the noise is

to

be

absorbed

is

called

encapsulation

EXAMPLE: Acoustic absorbers are applied to the hood, the bulkhead, the sides of the front beams and an under shield.

The encapsulation of the engine compartment arises from the need to reduce exterior noise

TRENDS


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Today, under shields are partially covered by an acoustic

material

or

made

of

an

intrinsically

absorbing

and

at

the

‐ .

Another trend is en ine‐mounted acoustic insulation components

on

the

oil

pan

and

in

the

area

around

the

fuel

injectors.

CONFLICTS


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A challenge for materials in contact with the engine is that

they

are

exposed

to

1. Strong vibrations,

.

3. Aggressive chemicals

4. Interfacing the shields with a very complex geometrical environment.

CONFLICTS


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5. Higher injection pressure,

6. Direct petro injection,

.

ADDED ADVANTAGE


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Reducing both fuel consumption and exterior noise

E icient encapsu ation can provi e a re uction in CO2 emissions by 2.5 g/km in the New European Driving Cycle (NEDC).

Underbody panelling can make a significant contribution towards reducing drag

NISSAN INFINITI


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NISSAN INFINITI


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The most recent study conducted

petrol engine shows that body-

mounted engine encapsulation can

reduce power train noise by 5 dB


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ENCAPSULATION WITH

RESPECT

TO

TEMPERATURE


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ENCAPSULATION WITH RESPECT TO

TEMPERATURE


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7 mm thick encapsulation covering 80 % of the

area is equivalent

to

50

mm

thick encapsulation

cover ng on y 0 ,

Therefore, the first priority in the development

o

an encapsu a on

s

e

g es

poss e

egree of area coverage rather than the choice of highly

.

NOISE REDUCION IN CI ENGINE


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Equipping parts of the engine air‐intake system with

porous

acoustic

materials

integrated

into

a

double‐

v v exterior noise quality of a diesel vehicle


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MATERIAL In 2007, a system of engine‐mounted parts

weighing less than 2.5 kg was presented . The

system provided

reductions

in

radiated

noise

in

the

engine test bench of 3 to 4 dB.

NEEDS


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combination of material optimisation,

o y ‐mounte an

‐

will be needed to achieve the le al re uirements for significant noise reduction

‐


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Body ‐mounted encapsulation is made of

components originating

from

acoustic

treatment:

The bonnet absorber,

Outer bulkhead and

Under‐engine

shield.

Vertical elements along the front beams form a tightly enclosed engine compartment

‐

ENCAPSULATIONl ll d h


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Electrically actuated shutters or

Other appropriate front closing elements

Limit heat and noise leakage through the radiator. The system must ensure an efficient flow of air through the radiator for optimum engine coolin durin drivin .

vibrations and operating temperatures are lower for body ‐mounted , .

BARRIERS IN

TAEE

ff d l f h l


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cost‐effective development of the sealing system

pass‐throughs for the steering column, drive shafts, cables and other interfaces need to be integrated.

ENGINE MOUNTED

ENCAPSULATION

E i d l i i ll b i fi d


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Engine‐mounted encapsulation is smaller but is fixed

to

surfaces

that

are

usually

hot

and

exposed

to

more

v y . materials with higher temperature resistance

THERMAL SAFETY


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SHELL DESIGN

R l l d th b t b b b i l


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Replace several covers and the bonnet absorber by a single element, thus allowing a significant weight reduction.

The construction comprises a lower and an upper shellmade of function‐s ecific, structurall and acousticall

optimised composite materials

ADDED ADVANTAGE

The double shell design efficiently combines the following:


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The double‐shell design efficiently combines the following:

1. high

noise

absorption 2. ig part sti ness

3. heat insulation

.

inlet

5. integration of pedestrian protection absorbers, electric

cables and devices.

BONNET DESIGN


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SHELL DESIGN


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MATERIALS

FOR

THERMAL

AND ACOUSTIC INSULATION IN THE

For engine‐mounted parts such as engine covers


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For engine mounted parts such as engine covers

1. Injecte po y propy ene coup e wit e t or po yuret ane foam‐ moulded absorbers are widely used

2. These material combinations are not suitable for a complete encapsulation due to their high weight between 3 and 4 kg/m2 .

BODY‐MOUNTED ACOUSTIC PARTS

Body‐mounted acoustic parts are often made of glass wool


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Body mounted acoustic parts are often made of glass wool or cotton felt, with phenolic resin as a binder treated .

Besides the good economics, these materials provide overall ood flammabilit resistance.

the resin has some disadvantages such as odour and VOC volatile organic compounds emissions.

NEW COMBINATION

A needled fibre material consisting of a combination of PP


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A needled fibre material consisting of a combination of PP and a variable amount of glass fibres in order to balance

such materials are not suited to the hi h tem eratures

close to

an

engine

since

they

are

limited

to

140

°C

(continuous engine surface temperature).

FUTURISTIC APPOROACH

Therefore there is a need to develop materials that


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Therefore there is a need to develop materials that

combines 1. mec anica strengt ,

2. acoustic effectiveness,

3. eat

nsu at on

an4. heat stability.

CONCLUSION It is foreseeable that the internal combustion engines of


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gfuture vehicles will require closed encapsulations in order

.

poses tremendous challenges for car manufacturers in terms of added complexity, weight, cost and thermal safety

pro ems.

REFERENCE [1] de ciutiis, h.; bürgin, t.; gorlato, l.: auswirkungen von verschiedenen motorraumkapsel‐

konzepten auf emissionen verbrauch und auf die thermische betriebssicherheit im


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konzepten auf emissionen, verbrauch und auf die thermische betriebssicherheit im motoPkws. In: Wärmemanagement des Kraftfahrzeugs. Expert Verlag, Renningen, 2006

[2] Lehmann,

D.:

Engineering

Process

for

an

Innovative

Underfloor Module.

Rieter

utomot ve on erence, r c , 2003

[3] Strategic Research Agenda of the European Road Transport Research Advisory Council, Dezember 2004

[4] Mantovani, M.; Lehmann, D.: Functional and Material Acoustic Optimization integrated . ‐ ‐

[5] Meschke,

J.;

Gaudino,

C.;

Bendell,

E.:

Design

and

Optimization

of

an

Engine

‐Mounted

Thermal‐ Acoustical Encapsulation. Rieter Automotive Conference, Zürich 2007

[6] Viktorovitch, M.: Acoustics of a Modular Engine Bay Encapsulation integrating a Porous . ,


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Automotive Pollution Control

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