optimization of muffler acoustics using gt-power · optimization of muffler acoustics using...

Optimization of Muffler Acoustics usingGT-POWER

Manish Dixit, Sundaram V, Sathish Kumar SFCA Engineering India Pvt Ltd

GT CONFERENCE INDIA 2015 – Pune, India.Dec 07, 2015.

©2015 FCA US LLC

Agenda

2

• Introduction

• Methodology

• Pre-Processing

• Transmission Loss

• Results & Correlation

• Acoustics Optimization

• Conclusions

©2015 FCA US LLC Dec 07, 2015GT CONFERENCE INDIA 2015

Introduction

3

Significance of Exhaust Tail Pipe Noise

Engine Performance

Pass By Noise norms achievement Cabin Interior and Exterior noise assessment Objective and Subjective noise assessment

Simulation Requirement

Tail pipe noise prediction with full engine model, engine performance validation

Accuracy of predicted results Reduced development time Reduced number of proto samples for testing ,saves cost and time


Acoustics Simulation Methodology

4

Conceptual Design / Muffler Tuning Code

Acoustics TargetsBack Pressure TargetsSystem Layout

Engine ModelEngine InputsInputs

Component Modeling - GEM3D & GT-SPACECLAIM

Exhaust System Modeling / Simulation – GT-ISE

Acoustic & Back Pressure Results Evaluation – GT-POST

Engine Bench Testing

Results Review / Design Freeze


Acoustic Development Flow Chart

5

Muffler Conceptual Design

Acoustics TargetsBack Pressure TargetsSystem Layout

Inputs from Supplier

Acoustics and Back Pressure Simulation

Engine Bench Test Validation

Noise Validation in Vehicle

Subjective Evaluation

Freeze Design

Transmission Loss

Tail Pipe NoiseOrder AnalysisBack Pressure


Pre Processing

6

GEM3D Discretization Discretized 1D Model

Muffler

Resonator


Transmission Loss (TL)

7

0 100 200 300 400 500 600 700 800 900 1000

Tra

nsm

issi

on

Lo

ss(d

B)

Frequency(Hz)

Test Baseline

• Four pole method simulation set up• White noise speaker : Sound Source• Anechoic termination: End Environment

• Better Correlation in low & mid frequency• Variation in results above 600 Hz


Inlet

Outlet

Results & Correlation:- Back Pressure & Tail Pipe Noise

8

1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

SP

L(d

BA

)

Engine Speed(rpm)

TARGET TEST BASELINE Order-2

1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

SP

L(d

BA

)Engine Speed(rpm)

TARGET TEST BASELINE Order-4

0 30 60 90 120 150 180 210 240 270 300

Bac

kP

ress

ure

(mb

ar)

Mass Flow Rate(m3/h)

TARGET TEST BASELINE BackPressure

1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

SP

L(d

BA

)

Engine Speed(rpm)

TARGET TEST BASELINE Overall

Baseline results are correlating well with test but not passing the target.


Acoustics Optimization with DoE in GT-POWER

9

DOE significance Parameterization of the model Definition of independent variables Selection of Simulation Methodology – DOE type

Optimization Parameters Inlet and outlet pipe diameter Tuned pipe diameter Position of Perforations on pipes Position of Baffles Glass wool density

Optimized Results Results obtained from DOE optimization are compared with Target

Perforations Position

Glass wool

Baffle Location

Inlet Pipe ø

Outlet Pipe ø


Tuned Pipe ø


11

1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

SP

L(d

BA

)

Engine Speed(rpm)

TARGET TEST OPTIMIZED Overall

1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

SP

L(d

BA

)Engine Speed(rpm)

TARGET TEST OPTIMIZED Order-4Order-2

0 30 60 90 120 150 180 210 240 270 300

Bac

kP

ress

ure

(mb

ar)

Mass Flow Rate(m3/h)

TARGET TEST OPTIMIZED BackPressure

1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

SP

L(d

BA

)

Engine Speed(rpm)

TARGET TEST OPTIMIZED

Baseline results are correlating well with test and at par with the target.

Conclusions

12

GEM3D is capable of discretizing muffler and resonator volume into proper subvolumes (flow splits) which has lead to good correlation in back pressure and tailpipe noise for baseline design.

The GT-POWER shows enhanced ability to conduct a complete system analysis(intake/engine/exhaust) with relatively low computational effort is a greatadvantage.

DoE integration in the simulation procedure is a significant step towards efficientproduct development providing optimized solutions.

The optimized results are at par with target in back pressure and tail pipe noise(overall and orders).


optimization of muffler acoustics using gt-power · optimization of muffler acoustics using...

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