pti_lecture_5.pdf

Knowledge Center

Air Induction SystemsAir Induction Systems

J k B hJack BahmGeneral Motors

Air Induction Engineering Group Manager

Content General Motors Copyright All Rights Reserved 1

Knowledge CenterAir Induction SubsystemAir Induction Subsystem

Introduction: Air Induction SystemInterfaces

System Content: Base & Optional Content

Functional Requirement: Air FiltrationAir Flow ManagementHydrocarbon Containment

Design, Develop, & Validate:

Induction Noise Attenuation

PackagingDesign, Develop, & Validate: PackagingAir FlowNoise & VibrationStructure

Content General Motors Copyright All Rights Reserved

Knowledge CenterAir Induction SubsystemAir Induction Subsystem

Camaro

Chevy Traverse


Knowledge CenterAir Induction System

ThrottleBody

AiAir Inlet


Knowledge CenterAir Induction System Interfaces

Vehicle Driver

Sound & Under hood Appearance

Motion, B d /

Government Compliance

RegulationsVibration, Mass

,Support, Space

Air

Body / Chassis

Regulations

Air / Contaminants/Thermals

Crankcase Ventilation, Hydrocarbons

AirInduction

Engine Subsystem

/Thermals

Measured(mass & temp)Filtered Air

SoundAmbient /Environment


te ed

Knowledge Center

Base and Optional Components

System Content

Base Optional

Base and Optional Components

Expansion chamber - (preplenum)

Seal/Clampassembly

Clean Air Duct - convolutes for flex

Clean air supply - vent system

Quarter wave tube

To Engine

y

Air Inlet - snorkel(venturi shape for

M.A.F. - mass air flow sensor

I.A.T. - inlet airtQuarter Wave TubeQuarter wave tube

Dirty Air DuctAir In

(venturi shape for noise reduction)

temp sensor

S.A.I. -secondary air inlet port

Quarter Wave Tube

Dirty Air DuctAir In

In-Line Resonator IsolatedAir Cleaner Asm- air filter element

inlet port


Branch Resonators

Isolated mounts - restriction indicator

- HC adsorbed

Knowledge CenterFunctional Requirements

The Air Induction System Provides the following main functions:

Air FiltrationAir Filtration

Air Flow Management

Hydrocarbon ContainmentHydrocarbon Containment


Other RequirementsOther Requirements



Air Filtration

Air Flow ManagementAir Flow Management


Oth R i tOther Requirements


Knowledge Center

AiAi

Functional Requirements


PARTICLE SIZE OF TEST DUST

35

40

e

Fine Dust

Coarse DustEngine

Automotive Filters

20

25

30

35

by V

olum

e Engine Wear

5

10

15

20

Perc

ent b

0

5

0 - 5 5 - 10 10 - 20 20 - 40 40 - 80 80 - 200Particle Size, micron


Knowledge Center

Relative Size of ParticlesRelative Size of Particles


Relative Size of ParticlesRelative Size of Particles

Particle Microns Inches

1 Micron

0.001mm=1μm=1 0.000039

• Visible by 10 0.00039N k d E

Dust- 12

Microns

Point ofStraight Pin75 Microns

Naked Eye

• Dust 12 0.00047

Pollen- 20 Microns

• Pollen 20 0.00079

• Point of 75 0 0029

Human Hair- 100 Microns

Point of 75 0.0029Straight Pin

• Human Hair 100 0.0039



98,000 actual customer miles

Dirty Air Filter Definition:A 2.5kPa (10”H20)

customer miles

Increase in ΔP

This part:Dirty = 13.15”H20Dirty 13.15 H20Clean = 12.80”H20ΔP = 0.35”H20

0.087kPa3 5% Di t !!3.5% Dirty !!@ 140 g/sec




Air Flow Management


Other Requirements


Knowledge Center



Air Flow ManagementAir Flow Management4 Cylinder Engine Simulation AnalysisEffect of Induction System Pressure Loss

120

140

98100102

werkP

a)

18%

Large Air Cleaner Inlet - kPa

Effect of Induction System Pressure Loss

60

80

100

92949698

Hor

sepo

w

t Pre

ss. (

k

5 kPa

18%

Small Air Cleaner Inlet - kPa

Large Air Cleaner Inlet - hp

20

40

60

84868890

Bra

ke H

ntak

e Po

r

Small AirCleaner Inlet - hp

08284In


Engine Speed - rpm

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MAF Signal Noise MAF Flow Deviation

Air Flow Effects on MAF Sensor

6%

5%

10%

8%

4%

3%

6%

4%

2%3%

2%

0

-2%

-4%

1%

0%

-6%

-8%


5 10 20 50 100 200 5 10 20 50 100 200Airflow (g/sec) Airflow (g/sec)



Hydrocarbon Containment


Flat Panel Type HC Absorber

Air Cleaner Cover

Pillow Type HC AbsorberHC Absorber

Paper Liner TypeHC AbsorberInside Clean Air Duct



Air Filtration

Air Flow Management




Knowledge Center




Noise Data130

120

Throttle Body Noise

100

110

(Source Noise)

vel,

dBa Induction System Attenuation

80

90

Noi

se L

ev

Vehicle/Body Attenuation

Induction Noise

(Snorkel Noise)

70

Drivers Ear Noise


60

2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000

Engine RPM


Pass-by Noise Measurements

Vehicle Procedure

• Microphonep

- 7.5 m +7.5 m +38 m

Start End Zone

Microphone•



Air Filtration




Water and Snow Ingestion

Filtered air to the PCV or Secondary Air Injection (SAI) systems


Knowledge CenterDesign Considerations

Packaging Induction System

Air FlowAir Flow

Acoustic / Noise & Vibration

StructureStructure

Other Considerations



Air Cleaner Shape & Location

Air cleaners should be a c ea e s s ou d be arectangular box shape to provided the best noise attenuation (expansion ratio) and the simplest shape for a panel air filter.



The inlet location must provide relatively cool, dry air to the engine

Air InletAir Inlet et

UpperUpper tie barradiator support

Headlamp


p


Packaging & Engine MotionClearance- Part to part variation

B ild i i- Build variation- Engine motion envelope- To other components:

• Exhaust componentsExhaust components• Air inlet opening• Engine mounted parts and any moving parts• Other stationary parts

Convoluted Duct

Convolutes




Air Flow


Structure




dDuct Bends: T i i i fl l th ti f th b d di ‘ ’ t

Duct Design

d To minimize flow losses, the ratio of the bend radius ‘r’ to the duct diameter ‘d’ should be greater than 1.5: r/d>1.5 (3.0 for turbo applications)

dInlet Bellmouth: A bellmouth at the inlet opening will reduce the turbulence and flow losses. The ratio of the flare radius ‘r’ to the duct di ‘d’ h ld b h 0 1r diameter ‘d’ should be greater than 0.15. r/d>0.15

4 Diffuser:

A ExitA Entry

Diffuser:A diffuser can be used in a duct to reduce noise and have minimal impact on flow. Use a 4o angle on each side and an area ratio equal to 4

A / A 4


A Exit / A Entry= 4


Pressure Loss Analysis


Knowledge Center

Press re Loss Testing

Design Considerations

AIR INDUCTION SYSTEMFLOW RESTRICTION

12.0

Pressure Loss Testing

10.0

6.0

8.0

stric

tion,

kPa

2 0

4.0

Res

0.0

2.0

28 55 83 111 139 166Flow g/s


Flow, g/s


MAFS

Air Flow Distribution & Velocity

Air flow through duct around MAFSAir flow through filter


Air flow through duct, around MAFSAir flow through filter


Air Flow Effects on MAF Sensor- Flow Tests

MAFS Signal Noise MAFS Flow Deviation


29


Evaluation of the Amount of Air Meter Variation Seen with Various Induction Systems

evia

tion

nt F

low

De 90 Deg. Bend Air Duct

Car A Car B

Target

Perc

en Car A Car B

1 10 100 1000

Flow ( grams / second )


( g )


The air induction system must minimize the amount of dirty air leakage into

Clean Air Leakagey y g

the clean air side of the system:

• Clean air side leakage can allow dirt and other contaminants to get into the engine Particles smaller than 5 microns should not affect the engine butengine. Particles smaller than 5 microns should not affect the engine, but larger parts may cause engine wear.

• Leakage between the MAFs and throttle body could result in a significant quantity of unmeasured (by the MAFs) air into the engine. This can cause fuel economy and drivability concerns.



7000120

Highway

Thermal Rise: Ambient to Throttle Body

5000

6000

80

100

ph

kph

Delta T< 5 i

Speed

3000

4000

60

C, S

peed

, k rpm

< 5 mins

1000

2000

20

40

Deg

rees

C

IdleHill Schedule<10o rise

000 500 1000 1500 2000 2500 3000 3500 4000 4500

Elapsed Time - seconds




Air Flowo


Structure




Noise Basics: Effects of Number of Cylinders

No. of Primary Orders I 4 Firing

E��

Cylinders & Multiples

4 (2, 4, 6, 8, etc..)6 (3 6 9 12 etc )

g‘ 1�2�4�3

1T��

0

5

1 0

1 5

2 0

2 5

3 0

0 2 00 4 00 6 00

L��

R��

6 (3, 6, 9, 12, etc..)8 (4, 8, 12, 16, etc..)2

30

5

1 0

1 5

2 0

2 5

3 0

0 2 00 4 00 6 00

0

5

1 0

1 5

2 0

2 5

3 05

1 0

1 5

2 0

2 5

3 0

0 2 00 4 00 6 00

Multiples or Harmonics

PrimaryOrder2 rev

40

0 2 00 4 00 6 00

0

5

1 0

1 5

2 0

2 5

3 0

0 2 00 4 00 6 00

2 rev

HarmonicsOrder 2 rev



Impact of Intake Manifold Design on Induction Noise Frequency Content

Intake manifold designEffective equal length runners

- High quality sound

- No odd or half order content presentNo odd or half order content present

Log style

- Poor sound characteristic

- Odd or half order content present


Knowledge Center

Engine Source Noise


Engine Source Noise Small Block 6.2L Gen IV Intake Manifolds

Car End Feed (LS3)Truck Center Feed (L92) ( )

Internal H l h l

( )

Helmholtz315 Hz



Engine Source Noise - Naturally Aspirated

* AIS consists of production air box with tuners removed


AIS consists of production air box with tuners removed

* Helmholtz tuner in center feed intake manifold was covered


Engine Source Noise Summary

The following affect the source sound pressure levels and spectral content that the AIS must act to attenuate. Changes to these will affect gthe required AIS tuning and required attenuation:• Number of Cylinders (active)

• Intake Manifold Geometry

• Intake air temperature (IAT)– combustion chamber pressures (DFSS Report 872)

• Cam Phasing

• Valve Overlap– Exhaust Manifolds

• Valve lift profile

• Bore diameter– Pressure /area

• Turbo charging



Air Induction System – Noise Sources

Radiated

Joint LeakageNoise

Radiated

Joint LeakageNoise

NoiseNoise

SnorkelNoise

SnorkelNoiseNoise

StructurallyT itt d

Noise

StructurallyT itt d


TransmittedNoise

TransmittedNoise


Noise Testing

120

130

Noise Testing

110

120

Throttle Body Noise

(Source Noise)

Ba Induction System Attenuation

90

100

e Le

vel,

dB

y

Induction Noise

70

80Noi

se Vehicle/Body Attenuation (Snorkel Noise)

60

70

2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000

Drivers Ear Noise

Engine RPM


Engine RPM


1/4 Wave Tube Tuning- (Effect of 1/4 Wave Tube Length)

atio

nNoiseThe resonant frequency of a 1/4 wave tube is directly

FrequencyAtte

nuaL

yrelated to the length of the tube.

Tuning of the 1/4 wave tube is q y

tenu

atio

Tuning of the 1/4 wave tube is achieved by defining the length as being 1/4 of the wavelength of the targeted

Frequency

Att

nat

ion

L = ¼ (c/f)

frequency.

FrequencyA

ttenu

aL = length of tube in mmc = speed of sound = 344,000 mm/sec


q ymm/secf = targeted frequency

Knowledge Center

Resonator (Helmholtz) Tuning


(Effect of Resonator Volume) (Effect of Neck Area) (Effect of Neck Length)

A

f

Resonator (Helmholtz) Tuning

Noise

f = resonantfrequency

d f

A L

Vc = speed of

soundA = cross-

sectional

atio

n Frequency

tio

Frequency

tion

area of neck

Le= effectivelength

Frequency

Atte

nua

Frequency

Atte

nua

n

FrequencyA

ttenu

a lengthof neck

V = volume ofchamber


Frequency Frequency Frequency


Expansion Chamber Tuning(Effect of Expansion Chamber Length)

Expansion Chamber Power(Effect of Expansion Ratio- ER)

/ 10/1ER= A1/A2>10/1

Frequency FrequencyA1

Frequency Frequency

atio

n

L

atio

n

A2

Frequency FrequencyA

ttenu

Atte

nu


Knowledge Center

Att t L ti N d A ti d d I l t Eff t


333 Hz Resonance 276 Hz ResonanceA

Attenuator Location - Node vs. Anti-nodes and Inlet Effects

AAnti-node Node

ANN

AA

AN NEn

gineNoise starts

at intake valve Noise starts

at intake valve

AA333 Hz 276 Hz

Helmholtz Resonators A= High Pressure AntinodeN= Low Pressure Node

AN

uctio

n

A AN

N NN

Air

indu

AirInletAir

Inlet

Nodes and Anti-Nodes are located throughout an induction system. The nodes are low pressure acoustic points while the anti-nodes are high pressure


acoustic points.


110

115

120

SNORKEL NOISE

Total Noise Target

)90

95

100

105

el, d

B (A

)

Frequency= (RPM x Order)/60

f=136 Hz

Total Noise Target

70

75

80

85

Noi

se L

eve

f=133 Hz

f=220 Hz

45

50

55

60

65

TOTAL SECOND ORDER

FOURTH ORDER

40

45

1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

Engine RPM



Pass by Test site:Microphone

Pass-by Test site: These Wide Open Throttle (WOT) Acceleration &

Locations

Deceleration exterior noise tests must be passed before vehicles may be sold in most locales, states and countries.




Air Flow


Structure




Duct Vacuum Collapse

Simulation Measured

Collapsed at 39.9 kPa40

(kP

a)

30

20

um L

evel

(10Va

cuu

0 2 4 6 8 10Time (seconds)

0




Air Flow


Structure





Ingestion of water and snow

Appearance / UH Harmony

Design For Assembly (DFA)Design For Assembly (DFA)

Design for Manufacturing (DFM)

Serviceability



Water Ingestion

Water Trough Test

Water Level (mm) J K L M N

A

B

Entry Speed (km/h)

Water Level (mm)

B

C

D

E



Water Trough – Test video


Knowledge Center

Snow Ingestion


Snow Ingestion

Air box-cover

Air filter

Air box-lower

Air Inlet


Under Hood Accumulation

Knowledge Center

SNOW INGESTION Video


Snow Ingestion Testing- On the test trackSNOW INGESTION Video


Knowledge CenterManufacturing Considerations

Material Selection

Operating Environment

Manufacturing Methods


- Recyclability

Design for Manufacturing- Design for Manufacturing

- Process Failure Mode Effects Analysis (PFEMA)

- Part to Part Variability


Knowledge Center

SummarySummarySummarySummaryAir Induction systems are asked to do many things:

Filter air

Measure air

Support Emissions

Attenuate Noise

and More…

Proper design and development is critical to ensure performanceProper design and development is critical to ensure performance meets all requirements.


Knowledge Center

Thank You!Thank You!Thank You!Thank You!


Knowledge Center

AppendixAppendixAppendixAppendix


Knowledge Center

Ai Cl A bl Th i l bl id l i t th i It

Air Induction System - Glossary

Air Cleaner Assembly: The air cleaner assembly provides clean air to the engine. It contains an air filter that removes contaminants from the incoming air. It also functions as an expansion chamber for noise attenuation. Air Filter: The air filter captures contaminants from the incoming air. The filter attachment is air tight to prevent leakageattachment is air tight to prevent leakage.Air Inlet: A snorkel or venturi, at the inlet of the air induction system, that prevents excessive separation of the air flow while minimizing air restriction and noise.Attenuation (acoustic): Describes how well a device silences noise.Clean Air Duct: The clean air duct assembly transports clean air from the air cleanerClean Air Duct: The clean air duct assembly transports clean air from the air cleaner assembly to the engine throttle body. Attachments for the clean air duct need to be air tight to prevent leakage and contaminant ingestion.Clean Air Supply: Attachments to the air induction system’s clean air supply may be required by other subsystems such as the Crankcase Ventilation System Theserequired by other subsystems, such as the Crankcase Ventilation System. These attachments need to be air tight to prevent leakage and contaminant ingestion.Dirty Air Duct: A duct assembly that connects the air inlet to the inlet of the air cleaner assembly. The attachment to the air cleaner assembly should be an air tight fitting to minimize air/noise leakage and contaminant ingestionminimize air/noise leakage and contaminant ingestion.Expansion Chamber: The expansion chamber is a bottle in the air flow path that functions as an accumulator to cushion induction pulses. It attenuates noise over a relatively wide range of frequencies.


Knowledge CenterAir Induction System - Glossary

Hydrocarbon Absorber: The hydrocarbon absorber captures the evaporated emissions from the engine and prevents them from escaping into the atmosphere.Intake Air Temp Sensor (IAT sensor): The IAT sensor measures the temperature of the clean air flowing to the engine. The attachment of the IAT sensor needs to be air tight to g g gprevent leakage and contaminant ingestion.Isolated Mounts: Isolated mounts are used to attach air induction components to body structures and cushion/isolate any component structural vibrations. Mass Air Flow Sensor (MAF sensor): The MAF sensor is an air meter that measures the air flow rate supplied to the engine. The MAF sensor is attached with an air tight fitting to prevent leakage and contaminant ingestion.Positive Crankcase Ventilation (PCV): This is the engine ventilation system and is connected to the clean air duct on the induction system as a source of fresh air.Quarter Wave Tube: A quarter wave tube is a capped tube used to attenuate induction noise. The length is one quarter the length of the wave targeted for noise attenuation.Resonator: A resonator is composed of a neck and a bottle that functions to reflect sound waves back to the engine. It may appear as a branch or in-line component. The neck size and length, along with the bottle volume, determine the noise attenuation. Restriction Indicator: This sensor measures the pressure difference across the air filter and is used to indicate when the air filter needs to be replaced.Seals and Clamps: Seals and clamps are used to form air tight attachments.


Knowledge CenterAir Induction System - Glossary

Secondary Air Injection (SAI) System: The SAI draws air from the clean air side of the airbox and provides air (oxygen) to the exhaust system to help the catalytic converter heatup to operating temperature. Transmission Loss: Indicates a device’s ability to attenuate noise. The device is subjected to a defined noise source and the exiting noise is measured. The differenceis the transmission loss, which is the noise attenuated by the device.Wide Open Throttle (WOT): This is the condition where the throttle blade is in the most open position possible.


Knowledge CenterAir Induction System - References

Ackeret, J., “Aspects of Internal Flow”, Fluid Mechanics of Internal Flow Symposium, GMR, 1965.Beranek, L.L., “Noise and Vibration Control”, McGraw-Hill Book Company, 1971.Davis, D.D., Jr., G.M. Stokes, D.Moore, and G.L. Stevens, Jr., “Theoretical and Experimental Investigation of Mufflers with Comments on Engine-Exhaust Muffler Design”, NACA rept. 1192, 1954.DuPont, “General Design Principles”, Design Handbook for DuPont Engineering Polymers, Sept 1992.Eversman, W. "A Systematic Procedure for the Analysis of Multiple Branched Acoustic Transmission Lines", ASME Transactions, Journal of Vibration, Acoustic, Stress and Reliability in Design 109(2), 168-177, 1987.Eversman, W. and Ricci, G.," A Multiple Degree of Freedom Cavity Element for Acoustic Transmission lines", ASME Transactions, Journal of Vibration, Acoustic, Stress and Reliability in Design 110(1), 76-83, 1988.Eversman, W. and White, J.A., Jr., 1993 Proceedings of NOISE-CON ‘93, Williamsburg, Virginia, May 2-5. Acoustic Optimization of Internal Combustion Engine Induction SSystems.Eversman, W. and White, J.A., Jr., 1994 Proceedings of NOISE-CON ‘94, Ft. Lauderdale, Florida, May 1-4. Transfer Function Techniques for Automotive Interior Noise Due to the Induction System.


Knowledge Center

Eversman W and White J A Jr Proceedings of 1995 SAE Noise and Vibration

Air Induction System - ReferencesEversman, W. and White, J.A., Jr., Proceedings of 1995 SAE Noise and Vibration Conference, Traverse City, Michigan, May 15-18. Acoustic Modeling and Optimization of Induction System Components.Eversman, W. and White, J.A., Jr., 15th International Congress on Acoustics, Trondheim Norway June 26 30 1995 Plane Wave and Finite Element Models ofTrondheim, Norway, June 26-30, 1995. Plane Wave and Finite Element Models of Induction Manifolds.Miller, D.S., “Internal Flow Systems”, BRA Fluid Engineering Series, Vol. 5, 1978.Nishio, Y., Kohama, T. and Kuroda, O., “New Approach to Low-Noise Air Intake System Development” SAE Paper 911042Development , SAE Paper 911042.Reneau, L.R., Johnston, J.P. & Kline, J.S. (1964)”Performance and Design of Straight Two-Dimensional Diffusers”. Report PD-8, Thermosciences Division, Mechanical Engineering Department, Stanford University, September 1964.SAE J726 “Air Cleaner Test Code” June 1987SAE J726, Air Cleaner Test Code , June 1987.Schumacher, Richard F., Convener ISO/TC 43/SC 1/WG 42, “ISO 362 Procedure”, letter with draft procedure included, Unpublished, October 27, 1995.Suzuki, T. and Kayaba, F., “The Analysis and Mechanism of Engine ‘Intake Rumbling Noise’” SAE Paper 901755Noise , SAE Paper 901755.White, J.A., Jr., 1996 SAE International Congress & Exposition, Detroit, Michigan, February 26-29, 1996, Air Cleaner Shell Noise Analysis with Plate and Shell Theory.White, J.A., Jr., GM Powertrain Noise Network Design Guide, Report No. AES-88-037R, September 1988 91 Induction System Acoustic Design Guidelines (ref 6M3 1)


September, 1988-91, Induction System Acoustic Design Guidelines (ref. 6M3.1).

Knowledge CenterAir Induction System - References

White, J.A. Jr. and Eversman, W., Recent Advances in Active Control of Sound and Vibration, Blacksburg, Virginia, April 28-30 1993. Analysis, Design and Evaluation of Active Induction Noise Control.White J A Jr and Eversman W SAE Worldwide Passenger Car Conference andWhite, J.A. Jr. and Eversman, W., SAE Worldwide Passenger Car Conference and Exposition & Conference, Dearborn, Michigan, October 25-27, 1993. Three Dimensional Induction System Acoustic Modeling with Acoustic Wave Finite Elements.

This presentation was derived from the Powertrain Integration class taught by Gary M i (GM Ai I d i T h i l E )Martinson (GM Air Induction Technical Expert).


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