9. Powertrain Noise & Vibration

8/12/2019 9. Powertrain Noise & Vibration

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Powertrain Noise & Vibration

N V KARANTH

Deputy Director, Head NVH Laboratory

The Automotive Research Association of India, Pune



Necessity of NVH AwarenessNecessity of NVH Awareness

!"ND I A PR!PA#ATIN# T$P% !& %N%R#$'

N!I% I A "N(ANT%D !"ND'

NOISE - AUDIBLE

VIBRATION - TATILE

HARSHNESS - TATILE AND AUDIBLE

)*+H - .//H0

1



Necessity for A!to"oti#e NVHNecessity for A!to"oti#e NVH

Noise Po22ution 3 45VR, 4P46 7 N4NP4

4ustomer A8areness !f Vehic2e Noise and Ride 4omfort

5ar9etabi2ity

Trend To8ards Hi:her Po8er and ma22er ie Po8er trains'

ound ;ua2ity

Desi:n !ptimiation

4onsistency In Production

.



<

PASS BY

NOISE

SPL

OEL

RIDE

COMFORT

SOUND QUALITY

EXTERIOR

NOISE

INTERIOR

NOISE





Sensiti#ity to Noise $ A"%it!'e an' (re)!ency

=


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Noise Sources-LevelsNoise Meter



NVH assification

6y Noise Type Road

(ind

Drive2ine

?uea9 and Ratt2e

6y Vehic2e ystems 6ody

4hassis

Drive2ine

Vehic2e components 42imate contro2

system (ipers

eat motors 8itches

@



NVH So!rces an' t*eir inter-reationNVH So!rces an' t*eir inter-reation

Power-trainPower-train

EngineEngine

TransmissionTransmission

Intake systemIntake system

Cooling systemCooling system

Exhaust systemExhaust system

Brake SystemBrake System

Road and TyreRoad and Tyre

WindWind

SuspensionSuspension

MountMount

VibrationVibration NoiseNoise

AirAir

OthersOthers

Harshness

Ride

Comfort

Sound

Quality



So!n' +!aity

ound ?ua2ity );0 is the perceptua2

reaction to the sound of a product that

ref2ects the 2istenerBs reaction to the

acceptabi2ity of that sound for thatproductC the more acceptab2e, the

:reater the ;

6oth obective 7 subective

assessments need to be made

*/



Pass-by Noise of A!to"oti#e Ve*ices

4ommunity Noise Po22ution')I-./1@EI!-.=10

5aFimum ound Pressure 2eve2 in Gd6)A0

measured at a distance of >'+m from the

vehic2e durin: vehic2e acce2erated to fu22

thrott2e

**




*1

1 0 m

10 m 10 m 10 m 10 m

1 0 m

A BP

A’ B’P’

Centre line of

travel R= 50 m

Microphone (Height 1.2 m)

Minimum area covered with test road surface (Test Area)

Note: There shall be no large acoustically reflective objects with in the radius




*.



E,ISTIN PASS - B. NOISE LI/ITS (OR AUTO/OBILES

*<



Interior Noise So!rces

*+

Intake SystemSurface Noise Radiation

Orifice Noise

System Vibrations

Exhaust SystemSurface Noise Radiation

Tailpipe Noise

System Vibrations

Transfer Behaviour

of Noise and Vibration

Vehicle

Interior Noise

Wind Noise

Drive Train Tyre

Wheel Suspension

Power TrainEngine and Gearbox Surface

Global Power Train Mode

Local Mode (P/T Mode, P/T Mount Brackets

Accessories)



Interior Noise of Ve*ice

*=



Power Train $En0ine Noise

Ty%es of En0ine Noise

Airborne Noise %Fhaust and Inta9e

tructureborne Noise Vibratin: surfaces

of en:ine structure and connected covers

*>



Power Train $En0ine Noise

/ain E1citation (orces an' Str!ct!re

borne En0ine Noise 2

4ombustion Noise "nidirectiona2 :as 7Inertia forces cause combustion

noise'

5echanica2 Noise Reversib2e forces reated

due to cran9 mechanism induce mechanica2

noise'

*@



Inta3e Noise

Noise #enerated due to

!penin: and c2osin: of the va2ves'

In2et air co2umn osci22ation by sharp

pressure pu2se from cy2inder'

*



E1*a!st Noise

%Fhaust va2ve opens and re2eases :as at hi:h pressureinto the eFhaust system'

The principa2 component of noise - &undamenta2 and

harmonics of firin: fre?uency'

1/

Exhaust system design is a compromise between noise

reduction and engine power loss due to increase in back

pressure.



!tc* Noise

42utch udder is basica22y torsiona2 vibration in thedrive 2ine durin: startin: of en:a:ement' This resu2ts

in rou:h starts and affects the ride comfort'

The maor causes are &riction characteristics of the c2utch i' e' re2ationship

bet8een s2ip speed and the friction coefficient

Torsiona2 vibrations due to variation in aFia2 2oad

resu2tin: from misa2i:nment of the drive2ine The c2utch peda2 vibrations can cause interior noise

prob2ems

1*



Trans"ission Noise

Drive2ine noise and vibration sources resu2ts from

transmission of po8er from the en:ine to 8hee2s'

Trans"ission 0ear noise2

6endin: dynamics of the individua2 :ear tooth'

6oth bendin: and torsiona2 dynamics of :ear shafts'

Type and precision of :ears used'

&undamenta2 and second harmonics of the :ear mesh fre?uency -

most si:nificant components of :ear noise'

11



Trans"ission Noise

Dri#es*aft an' Pro%eer s*aft 2

%Fcitation at rotationa2)fundamenta20 speed'

"niversa2 oint can provide eFcitation at secondorder

due to hi:h an:2es of coup2in:'

Rear 8hee2 drive vehic2es emp2oy a constantve2ocity oint in the center oint of t8o piece

prope22er shaft - provides aFia2 comp2iance in the

drive2ine 8hich decoup2es vibration from rear aF2e'

1.



ear w*ine 0enerate' by 0ear "es* of t*e'ifferentia4

Vibration eFcited by tooth meshin: action of the aF2e :ear

set'

Noise is narro8 band and annoyin: even at 2o8 2eve2s in the

passen:er compartment of the vehic2e'

Noise due to resonance mode of the aF2e may be reduced

by a2terin: aF2e mass and stiffness so that resonance 2ie

outside the norma2 operatin: ran:e'

Dri#eine-A1e Noise

1<



Bet Noise

J Impact :enerated by co22ision oftooth of be2ts a:ainst bottom2and of

sproc9et at the be:innin: of

meshin:

J Transverse and torsiona2 vibrationof the be2t

J Airf2o8 bet8een be2t and pu22ey at

meshin:

J &riction bet8een be2t and pu22eyand s2ip of the be2t

J Vibration of the pu22ey

1+



*ain Noise

J Impact of chain 8ith sproc9et and

po2y:ona2 effect

J Ro22er impacts of chain at hi:her

speedJ Torsiona2 vibration of camshaft

causes si:nificant tension f2uctuation

in chains and ma:nifies chain

transverse vibrationsJ 4hain natura2 fre?uencies

J 4over fre?uencies

1=



Tyre noise is :enerated by,

Ro22in: contact of the tyre

)a resonant system0 8ith surface of

random rou:hness )the road0'

Trea' #ibration - Radia2 vibration of

tread - primary contributor noise'

Trea' s)!ir" - Loca2ied 2atera2

vibration of tread - hi:h fre?uency part

of noise spectrum'

1>



So!rce5Pat*5Recei#er

1@

Source - causes disturbance

Path - may isolate or amplify disturbance

Receiver - responds to disturbance NVH strategy

Source X Path Sensitivity = Response



NVH Toos an' /et*o's

ource identification ound Intensity ound Acoustic Ho2o:raphy

5oda2 ana2ysis %Fperimenta2 5oda2 Testin: !peratin: Def2ection hapes !perationa2 5oda2 Ana2ysis

!peratin: 5easurements !rder trac9in:

Noise Path Ana2ysis 4A% ound ;ua2ity

ound synthesis ury %va2uation

1



So!n' So!rce I'entification

ound Intensity !btain vector ?uantity of sound at various pointsE:rid 2ocations

around the test artic2e usin: a 1-microphone probe

./



Acoustica2 Ho2o:raphy and 6eam &ormin:

Ho2o:raphy is Gmeasurements of a wave field are

made on a two dimensional surface and is used to calculate

wave field in three dimensional space to obtain a visua2

representation of the sound radiated from a test artic2e usin: a

microphone array'

.*

Vehicle Exterior Vehicle Interior Engine Noise



Noise ontrib!tion of Vario!s o"%onents of En0ine

.1

E1*a!st

syste"-678

Inta3e syste"-

978

Ot*ers-678

En0ine Boc3-

678



/o'a Anaysis

..

E/A /ODE 2 6:; H< (EA /ODE2 6:7 H<

E/A /ODE 2 =>9H< (EA /ODE2 =?= H<

E,PERI/ENTATION (E ANAL.SIS



ODS $ O%eratin0 Defection S*a%es

!peratin: Def2ection hapes 3

5easure motion transmissibi2ity

functions re2ative to one fiFed

2ocation, ) acci E acc 0 at a 2ot of

points, 2i9e 8ith 5oda2 Ana2ysis It 2oo9s 2i9e a duc9, but ITB N!T A

D"4K )mathematica22y, these are

forced response shapes, not mode

shapes - itBs N!T moda2 ana2ysis0

4an be time-domain or fre?uency

domain

Laser Vibrometer

.<



Vibro-aco!stic Pre'iction Tec*ni)!e

.+



/!ti-bo'y 'yna"ics

4omponents mode2ed as ri:id, 2umped mass part 4onnections throu:h sprin:s and dampers "nderstand traectory and time-response of system

As in suspension systems, steerin: systems, ri:id-bodyvibration modes of po8ertrain )bounce, pitch, ro220

Lo8 fre?uency )be2o8 *// H0 ADA5 is popu2ar 4A% soft8are for this type of mode2in: "sed as support for 6oundary 4ondition for &%5

.=



Noise Pre'iction by (E/ Tec*ni)!e

&% 5oda2 Ana2ysis

Dynamic Response Ana2ysis

4oup2ed Ana2ysis

.>



BE/ Tec*ni)!e

It is one of Numerica2 techni?ues

used to so2ve the acoustic prob2ems

2i9e &inite %2ement 5ethod)&%50'J In 6%5 on2y the boundary of the

domain is dicsretied' &or comp2eF

#eometries the 6%5 mode2in: 2eads

to si:nificant savin:s of manpo8erand computationa2 time'

.@



Ot*er AE Tec*ni)!es

tatistica2 %ner:y Ana2ysis Hi:her &re?uency computationa2 NVH

techni?ue, usua22y used at fre?uencies hi:her

than .// H in automotive app2ications

4omputationa2 &2uid Dynamics App2ied to f2uid-f2o8 and air-f2o8 )e':' 8ind

noise0

.



orreation Between (E Tec*ni)!e an' E1%eri"enta Testin0

</

Test /o'e

Initia (R(s

/o'e Test



orreation Between (E Tec*ni)!e an' E1%eri"enta Testin0

<*

9.70E+01

1.17E+02

1.37E+02

1.57E+02

1.77E+02

1.97E+02

2.17E+02

630 800 1000 1250 1600 2000 2500 3150

4entre 6and &re?uency in M H, M

V i b r a t i o n V e 2 o c i t y

LOC 01 LOC 2

LOC 03 LOC 07

200 250 315 400 500 630 800 1000 1 250 1 600 2000 2 500 3 150 4 000

Centre Band Frequency (Hz)

V i b r a t i o n V e l o c i t y_

V-Loc 1 V-Loc 2

V-Loc 3 V-Loc 7

VIBRATION VELOCITIES WITH

COMBUSTION FORCES

/EASURED VIBRATION

VELOITIES



Aco!stica Treat"ent

<1



Ri'e o"fort

<.

Ride - Tactile And Visual Vibrations, 0 - 25 Hz

Vibrations - Noise Aural (25 Hz - 20 kHz)

EXCITATION

SOURCES

Road roughness

Tire/Wheel

Driveline Engine

VEHICLE

DYNAMIC

RESPONSE

VIBRATIONS

Ride Perception



Ve*ice Ri'e o"fort

Ride comfort in a vehic2e is a subective perception norma22yassociated 8ith 2eve2 of comfort eFperienced durin: trave22in: in

a vehic2e'

Perceived ride is cumu2ative effect of many factors'

In the vibration spectrum,

Ride - / -1+ H

Noise - 1+H - 1/KH'

Ride is a tacti2e and visua2 vibrations'

<<



Ve*ice Ri'e o"fort

Vertica2 fre?uencies 8hich fee2s most uncomfortab2e fa22s in the

ran:e of 1/H - 1//H'

&ati:ue occurs most rapid2y 8hen subected to vibrations in the

ran:e of <H to @H or in the 2o8 band be2o8 /'>+ H 8herediiness and motion sic9ness can resu2ts

Latera2 or foreEaft fre?uencies in the same ran:e are a2so

uncomfortab2e because it disturb ba2ance of inner ear'

I!1=.* for eFposure 2imits of 8ho2e body vibrations and

I!+.< for eFposure to hand arm vibrations'

<+



Noise Iss!es '!rin0 Ve*ice O%eration an' /aintenance

%n:ine

5ountin: of en:ine and top cover

5ismatch of mass bet8een piston and connectin: rods

4ran9 shaft ba2ancin:

Torsiona2 vibration

%Fhaust

Loose mountin: 6rac9ets

Lea9a:es

4orrosion

6aff2es in muff2ers

hie2din: materia2

<=



Noise iss!es '!rin0 Ve*ice o%eration an' "aintenance

Trans"ission

/o!ntin0 of 'ifferentia an' s*oc3 absorbers

!tc* @!''er

Pro%eer s*aft .o3e ai0n"ent /isai0n"ent of r!bbers an' S%it s*aft syste"s

Bo'y

Vibrations of ire *arness t*at are ro!te' t*ro!0* brac3ets we'e' to bo'y

Steerin0

P!"% bets an' rac3 "ec*anis"s

Door

Swein0 of r!bber seas or si%%in0 action of r!bber seas for win'ows

/o#in0 0ass win'ows act!ators are not 'esi0ne' for re)!ire' tor)!e

<>



Ve*ice

teerin: Imba2ance of the 8hee2 8i22 induce vibration in

steerin: 8hee2

Looseness in trac9 and tie rods

6a22 oint 8earin: off

Knuc92e bearin:s 8earin: off

(hee2

Loose 8hee2 caps

(ashers for fitments

Nut conica2 and f2at )conica2-inside, f2at-outside0

<@



Ve*ice

Pane2s 6onnets, 2atch

oint 8hich are not 8e2ded homo:eneous2y

After accident some of the pane2s are not oined

proper2y

Dashboard

Air-conditionin: unit

eat

2idin: rai2s

<



Ve*ice

Trun9 Latches and hin:es, Tension bar inside

uspension Rubber mounts, functionin:

(ipe mechanism 5otors, (iper pads

Timin: drives 4hains noise are overcome by usin: be2t

Accessories

Va2ve mechanisms

Tyre

Pump noise

6attery

&an noise

Pipes

+/



ENINE NOISE- AN OVERVIE

+*



De"an' & Necessary

To'ayCs De"an'

*' Li:hter %n:ines 8ith hi:h compressions,

faster combustion 7 sma22er fue2

consumption'1' Lo8 noise en:ines4

*y it is Necessary

*' trin:ent Noise Le:is2ation

1' 4omfort

+1



Brea3 'own of %ass by noise in a ty%ica #e*ice

+.



*y Re'!ce En0ine Noise

5ore than +/ of sound po8er is radiated from

en:ine '

%n:ine 2oad carryin: 4omponents and Non-Load

carryin: covers are responsib2e for noise radiation'

+<



Noise Baance of en0ine

++



Noise eneration Process in Diese en0ines

+=

Research by LUCAS CAV



Ty%es of En0ine Noise

J Airborne Noise %Fhaust and Inta9e

J tructure borne Noise Vibratin: surfaces of

en:ine structure and connected covers

+>



Para"eters To Be /eas!re'-

J ound Pressure Leve2 at *mtr distance

J ound Po8er Leve2

J ound ;ua2ity

ritica O%eratin0 Para"eters2

J Rated and 5aFimum Tor?ue

J 5aFimum Rpm'

J Acce2eratin: conditions

+@



ENINE NOISE /EHANIS/ /EASURE/ENT

ound Po8er 5easurement

I! .></ and I! =*< series of standards

ound Pressure 5easurement &re?uency

ana2ysis by narro8 band and octave ana2ysis

+



E)!i#aent En0ine Syste"

=/



/ain e1citation forces

J as forces

J Inertia (orces

J /ec*anica I"%acts

=*





/ain E1citation (orces an' Str!ct!re borne En0ine Noise

4ombustion Noise "nidirectiona2 :as 7

Inertia forces cause combustion noise'

5echanica2 Noise Reversib2e forces

created due to cran9 mechanism

induce mechanica2 noise'

=.



/ain Para"eters to be controe'

J %Fcitation &orces

J Dynamic 4haracteristics of structure

J Noise Radiatin: characteristics of structure

=<



Noise Ra'iation /ec*anis"

=+



.LINDER PRESSURE AND NOISE SPETRA O( A T.PIAL DIESEL ENINE

==



NOISE SOURE IDENTI(IATION TEHNI+UES

#reatest Noise Reduction is achieved by identifyin:

the 5aor Noise ource and its 4ontro2'

Partia2 %nc2osure Techni?ue'

Acoustic Intensity Techni?ue

!rder Trac9in: Ana2ysis

Near &ie2d Acoustic Ho2o:raphy

=>



SOURE IDENTI(IATION 2 PARTIAL ENLOUSRE TEHNI+UE

Traditiona2 imp2e Techni?ue'

No pecia2ied 5easurement %?uipment or &ie2d Is

Re?uired'

Time 4onsumin:

ound Insu2ation Treatment is must and cost2y'

5ay 4han:e %n:ine Performance

Accuracy Depends on Insertion 2oss of oundInsu2ation Treatment'

=@




5a9e the Desired 5easurements 8ith en:ine

comp2ete2y eFposed'

App2y the ound Insu2ation treatment to the entire%n:ine'

Repeat the 5easurement '

4a2cu2ate the Insertion 2oss of ound Insu2ation

treatment confirm that it shou2d be O or */d6'

=




5a9e the ound 5easurement 8ith each noise

source eFposed individua22y'

Repeat the 5easurement a:ain 8ith sound insu2ation

treatment enc2osin: entire en:ine to ensure the

insertion 2oss of treatment'

4a2cu2ate the contribution of each source by

comparin: tota2 sound pressure 2eve2 and individua2

source'

>/



SOURE IDENTI(IATION 2 AOUSTI INTENSIT. TEHNI+UE

J ound Intensity I)t0

Instantaneous rate of f2o8 of ound ener:y per unit

surface area in the direction of 2oca2 instantaneousacoustic partic2e ve2ocity' This is a vector ?uantity and

is e?ua2 to the product of the instantaneous sound

pressure p)t0 at a point and the associated partic2e

ve2ocity v)t0'

>*

)v(t p(t)* )I(t −−

=




>1

• Sound Intensity: I(t):

It is expressed in Watt per Sq.meter.

Sound Power Level: SW : Sound Power is the measure of total sound energy

radiated by source.It can be calculated as,

S t I SW Q0)=

It is expressed in “ Watt “






ISO 9614 Series is available or calculation ofSound !ower b" sound intensit"

#easurement$

5ethodo2o:y

*'cannin: 5ethod

1'Discrete point 5ethod'

Procedure

--Discretie the 5easurement urface into Gn

sma22 se:ments )i0'

><




4arryout the norma2 ound Intensity GI)i0

5easurement at each divided se:ment )i0 of

area Gs around the source'

-- 4a2cu2ate a po8er for each e:ment GPi

-- &ina22y 4a2cu2ate Tota2 ound Po8er G('

>+

si I !i Q0)=

∑==

n

i

!i SW *



SOURE IDENTI(IATION2 ORDER TRAIN ANAL.SIS

!rder is inte:er or ha2f inte:er mu2tip2e of

cran9shaft rotationa2 fre?uency

!rders are cate:arised as G%venorders,!dd orders and ha2f en:ine !rders

%ven !rders are the mu2tip2es of firin:

fre?uency and provides the basic character of

noise'

>=



SOURE IDENTI(IATION2 Or'er trac3in0 Anaysis2 2 Utiity

To identify the noise :enerated by rotationa2

vibrations ,critica2 speeds and resonances'

It provides information of the noise 8ith

respect to en:ine rpm'

>>



SOURE IDENTI(IATION2 Or'er trac3in0 Anaysis

5%TH!D

ynchronous amp2in: 5ethod'

peed 8eep

Data can be Disp2ayed by

(aterfa22 Dia:ram

4ampbe22 Dia:ram'

>@





SOURE IDENTI(IATION2 Or'er trac3in0 Anaysis

In 4ampbe22 Dia:ram ,the fre?uency spectrum

of vibration is disp2ayed for different en:ine

RP5 and pea9 amp2itudes are p2otted 8ithfre?uency onto vertica2 aFis and the speed on

the horionta2 aFis 'The en:ine orders are

mar9ed a2on: dia:ona2 2ines'

@/



SOURE IDENTI(IATION2 NEAR(IELD AOUSTI HOLORAPH.

The basic princip2e of acoustic ho2o:raphy is

-G to measure cross-spectra bet8een a set ofreference transducers and the ho2o:ram

microphones over a p2ane c2ose to the

radiatin: surface'

@*



SOURE IDENTI(IATION2 NEAR(IELD AOUSTI HOLORAPH.

&rom this type of measurement a comp2ete .-D

description of the sound fie2d can be identified interms of ound intensity, partic2e Ve2ocity, ound

pressure 2eve2s, sound po8er and radiation

patterns'

@1



Str!ct!ra Res%onse

J It is essentia2 to understand the response of

the structure to the app2ied forces

J %va2uated by computin: the transfer

functions bet8een the eFcitation force and

vibrations at various 2ocations

@.



Str!ct!ra Res%onse2 /o'a Anaysis

J Natura2 &re?uencies, dampin: va2ues and

mode shapes are determined

J 5ode shapes are the deformation patterns

associated 8ith the natura2 fre?uencies

@<



/o'a set !%

@+



NOISE PREDITION TOOLS FNPTG

&inite %2ement Ana2ysis

Ray2ei:h Inte:ra2 5ethod

6oundary %2ement 5ethod

tatistica2 %ner:y Ana2ysis'

@=



NPT2 (inite Ee"ent Anaysis

5athematica2 Representation of the structure 8ith

respect to the :eometry, density)mass0,

stiffness, materia2 Properties and dampin: bydiscretiin: the structure into sma22 se:ments ca22ed

as G%2ements bounded by end points 9no8n

asGnodes

@>





NPT2 (inite Ee"ent Anaysis 2 /o'a Anaysis

It determines the free free ei:en va2ues 9no8nas natura2 fre?uencies and ei:en vectors as

mode shapes'

It is very usefu2 to va2idate the finite e2ementmode2s of the structures usin: %Fperimenta2

5oda2 Testin:'

It :ives re2ative amp2itude of different parts of

the structure in particu2ar mode,but it does

not :ive any information about abso2ute

response of the structure'

@



NPT2 (inite Ee"ent Anaysis 2Har"onic Res%onse Anaysis

It is a2so 9no8n as forced response ana2ysis'

It is used to predict the structura2 response

caused by a defined dynamic eFcitation'

&rom the dynamic Response characteristics

the surface ve2ocities are computed and 8i22

be used as input for 6%5 and

Ray2ei:h Inte:ra2 5ethod to find out sound

po8er and radiation ratio'

/



NPT2 (inite Ee"ent Anaysis 2Har"onic Res%onse Anaysis

Preparation of &inite %2ement 5ode2 of the%n:ine 4omponents 2i9e 4ran9case ,oi2

pan,shaft,covers,etc'

Va2idation of &inite %2ement 5ode2s of en:ine

compnents usin: &inite %2ement 5oda2

Ana2ysis in &ree &ree 4ondition and

%Fperimenta2 5oda2 Testin:'

App2ication of correct 6oundary 4onditions'

4omputation of urface Ve2ocities by &orced

Response Ana2ysis'

*



NPT2 RA.LIEH INTERAL /ETHOD

It is an approFimate radiation inte:ra2 in 8hich

it is assumed that the radiatin: surface is f2at

and 2ies in an infinite f2at baff2e and surface ofstructure is covered 8ith a finite number of

pistons 8hich move perpendicu2ar to the

surface 8ith certain Ve2ocities'

1

S.STE/ATI NOISE REDUTION STRATE.




.

Experimental Noise

Source Identification

Va2idated &%

5ode2

Yes

Preparation of

FE Model of

Noisy Component

Prototype of

Noisy Component

No

Refined FE

Model

Modal Data or FRF

Matching

Power train

Noise ontro

Experimental

Modal TestingAnalytical

Modal Analysis





<

Noise Prediction

using BEM

Structural Modification on

FE Model

Target Noise

Reduction is

Achieved

Product with

Reduced NoiseStructural Modification

on Prototype

Yes

No

Yes

No

Required

Noise Reduction is

Achieved

(using BEM)

Vai'ate' (E /o'e

Dynamic Response

Analysis using FEM

t '



ase st!'y

En0ine Asse"by Str!ct!ra

O%ti"i<ation for Low Noise Ra'iation

+

St t O ti i ti E i I ( i St



Str!ct!ra O%ti"i<ation E1ercise In#o#es (oowin0 Ste%s

Setting up target for Sound Power Level (SWL) reduction from base

Preparation of iterative models of varying stiffness by addition of

stiffners and ribs on crankcase and oil pan using Hypermesh

Forced esponse !nalysis " !pplication of unit force at bearing

location on F# model to predict surface vibration velocities

!coustic #ngine $esh Preparation using L$S % &irtual Lab Surface &elocity prediction of the assembly using L$S % &irtual

Lab '&H module

Surface velocity data transfer on acoustic meshed model

SWL Prediction and comparison with base SWL using L$S %

&irtual Lab !coustics

Selection of optimied models based on maimum SWL reduction

and minimum weight increase

=

E i t N i S I' tifi ti



E1%eri"enta Noise So!rce I'entification

>

Identification of noise pockets by

measuring/mapping noise at one

plane/surface .

Sound intensity/Acoustic holography

Setting up target for Sound Power Level (SWL) reduction from base

&% 5 d 2 f N i 4 t



&% 5ode2 of Noisy 4omponent

@

FE model for natural frequency correlation.

Modal analysis

V 2id t d &% 5 d 2 f N i 4 t



Va2idated &% 5ode2 of Noisy 4omponent

En0ine Asse"by

8 Variation in nat!rafre)!ency

%Fperiment &%-imu2ation

&re?uency Dampin: &re?uency

* $* * /'1=

1 $1 1 <'1=

. $. . */'*

< $< < /'+=

+ $+ + <'@<

FE model for natural frequency correlated.

Dyna"ic Res%onse Anaysis



Dyna"ic Res%onse Anaysis

*//

Forced esponse !nalysis " !pplication of unit force at bearing location

on F# model to predict surface vibration velocities and compared with

eperiment*

S!00este' /o'ification 92 /ain Ho!sin0



S!00este' /o'ification-92 /ain Ho!sin0

*/*

Base Model

S!00este' /o'ification2 ear bo1 co#er



S!00este' /o'ification2 ear bo1 co#er

*/1

S!00este' /o'ification62 !tc* Ho!sin0



S!00este' /o'ification62 !tc* Ho!sin0

*/.

Base Model

Preparation of iterative models of

varying stiffness by addition of

stiffners and ribs on crankcase and

oil pan using Hypermesh

En0ine /o'e Str!ct!ra & Aco!stic



En0ine /o'e $ Str!ct!ra & Aco!stic

*/<

!coustic #ngine $esh Preparation using L$S % &irtual Lab

Noise Pre'iction



Noise Pre'iction

*/+

orreation /eas!re' an' Pre'icte' So!n' Intensity /a%s



orreation- /eas!re' an' Pre'icte' So!n' Intensity /a%s

*/=

Aco!stic Bo!n'ary con'itions



Aco!stic Bo!n'ary con'itions

+mposing fre,uency dependent surface vibration velocities

generated earlier on engine assembly acoustic mesh and preparation of +S- field point mesh

*/>

ISO Field Point Mesh

Acoustic

Mesh

Reflecting Surface



SL o"%arison between Base an' Pro%ose'



SL o"%arison between Base an' Pro%ose'

*/*/

Modification

Base

:'BFAG re'!ction fro" Base SL

Noise re'!ction ac*ie#e' by /o'ifications



%arious desi&n iterations are compared on the &rounds

of percenta&e increase in assembl" wei&ht due toaddition of ribs' stiffeners etc$ and correspondin&

reduction in SW( level

)onsideration of noise aspects earlier in the desi&n

phase &ives strate&ic advanta&e to en&ine

manufacturers as the" can deliver low noise radiatin&

en&ines with minimum increase in en&ine wei&ht

Noise re'!ction ac*ie#e' by /o'ifications

/o'ification n!"ber Noise re'!ction in

'BFAG

ei0*t increase F30G

6ase

5odification-*

5odification-1 $$ $

5odification-.

**/



INTAK% AND %HA"T$T%5

***

Inta3e An' E1*a!st Syste" o%ti"isation



Inta3e An' E1*a!st Syste" o%ti"isation

Re?uire parameters

Insertion Loss )IL0

6ac9 Pressure )6P0

Transmission 2oss )TL0

**1

Sc*e"atic Test Set!%



Sc*e"atic Test Set!%

**.

Insertion

Loss

Trans"issionLoss

/EASURE/ENT O( IL ON E,ISTIN & TARET SILENER



/EASURE/ENT O( IL ON E,ISTIN & TARET SILENER

**<

IL = SPL1 – SPL2

Schematic of IL measurement

TEST SILENCER

Engine

SPL1

SPL2

Engine

WITHOUT SILENCER

/EASURE/ENT O( BP ON E,ISTIN & TARET SILENER



/EASURE/ENT O( BP ON E,ISTIN & TARET SILENER

**+

Test silencerEngine

Pressure taps

E,ISTIN SILENER (OR BP



E,ISTIN SILENER (OR BP

**=

Press!re Distrib!tion Veocity Vectors Distrib!tion

BP Predicted by CFD in mm Hg

Measured BP was in mm Hg

Variation of XX % is observed. This is generally considered as an acceptable

level considering the number of assumptions in the input and model during simulation.

SUESTED /ODI(IATIONS O( E,HAUST S.STE/



SUESTED /ODI(IATIONS O( E,HAUST S.STE/

**>

Tube 1

Tube 2

Tube 3Tube 4

!""le 1 !""le 2

Chamber 3Chamber 2

Chamber

1

!""le 2

Tube 2

Tube 1

!""le 1

Tube2

Ch!#ber 3Ch!#ber 2Ch!#ber 1

!""le 2

Tube 1

Tube 2

!""le 1 !""le 2

Chamber3Chamber2Chamber1

O/PARISON O( TL RESULTS O( E,HAUST S.STE/



O SO O SU S O US S S

**@

RESULTS O( BP AND IL /EASURE/ENTS ON PROTOT.PES



**

5uff2er

5ode2 E1istin0

Benc*"ar3Desi0

n9Desi0n

Desi0n

6sa"%e

9sa"%e

sa"%e6

Tar0etsa"%e

9

6P

)mmH:0

p ? r s t> u v

IL)d6A0

F y d a b c



NVH lab – Transforming Noise to Sound

Documents

9. Powertrain Noise & Vibration