Fuel Injector Design Optimization using GT-SUITE · 2016-07-01 · RBEI/EEI4 | 10/14/2015 | ©...

RBEI/EEI4 | 10/14/2015 | © Robert Bosch Engineering and Business Solutions Private Limited 2015. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.

GT Conference- Fuel Injector Design Optimization

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Fuel Injector Design Optimization using GT-SUITE

GT Conference 201507/12/2015

Aurobbindo L



Agenda

1 Motivation/Objective

2 Modeling approach

3 Simulation and Validation

4 DOE setup and Simulation

5 Summary

RBEI/EEI4 | 10/14/2015 | © Robert Bosch Engineering and Business Solutions Private Limited 2015. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.3



2 Modeling approach



5 Summary



4

Motivation for simulationUse of simulation in early development phase

Enable evaluation of new concept before the hardware exists

Identify the optimal design parameters with given constraints before the

hardware development

Reduce number of prototypes developed

Reduce actual hardware testing time

Objective: To determine the optimal Fuel Injector design parameters to

achieve the target fuel flow rate




2 Modeling approach



5 Summary

5


Modeling approachGT Conference- Fuel Injector Design Optimization

Main requirements of Injector: Target Fuel Flow rate Spray atomization Penetration depth Spray shape Spray size -SMD

Based on Fishbone analysis , the influencing parameters have been identified which would determine the flow rate

3D Injector model

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Fuel supply pressure



Modeling approach Contd., Understand Injector construction from 3D & AutoCAD drawings & Build

Injector Model using Hydraulics & Pneumatics Library in GT-SUITE

Parameterization of model to achieve desired Injection profile

Achieve pressurized injector flow rate as per injector specifications in the

simulation

Changes in the boundary conditions like supply pressure and observe if

the model could capture the flow dynamics

Match low pressure injection test bench data results with simulation

results

Conduct DoE to achieve the target Fuel flow rate with low pressure




2 Modeling approach



5 Summary



9

Injector model built in GT-SUITE and its output behavior for pressurized system

Simplification:The electromagnetic

circuit is built as a force lookup table

Posi

tion

[mic

ron]

ECU

sig

nal

Posi

tion

[mic

ron]

Mas

s Fl

ow R

ate

[g/m

in]

Pres

sure

[bar

]



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Simulation Test bench Simulation Test bench

Operating Pr bar 2.7 2.7 3 3

Needle Lift Microns 60 60 60 60

On time ms 2.5 2.5 2.5 2.5

Static Flow g/min 109 110 116.9 116

Dynamic Flow mg/Pulse 3.3 3.3 NA NA

Test bench and simulation results comparison

Sensitivity Analysis of 1D Simulation model

Flow rate variation with different operating pressure

Dynamic Flow rate variation with varying On time

Static flow rate variation with varying lift

2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1

Dyna

mic

Flo

w (m

g/St

roke

)

Operating Pr(bar)

Dynamic Flow @ varying On time

2.5ms60MicronLift 4ms60MicronLift



2 2.5 3 3.5 4 4.5 5

Dyn

amic

Flo

w (

mg/

Stro

ke)

OnTime(ms)

Linearity

`@2.7bar`3bar`4bar

2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1

Stat

icFl

ow(k

g/hr

)

Operating Pr(bar)

StaticFlow V/s Operating pressure

60MicronLift

80MicronLift

100MicronLift

mailto:@2.7bar



Instantaneous mass & Pressure inside sac Volume for low pressure system

Mas

s Fl

ow R

ate

[g/m

in]

Pres

sure

[bar

]

Sac Volume

Note: As the duty cycle is increased more fuel flows into the sac volume and gaseous volume fraction decreases and density increases

11

Popp

et L

ift [m

icro

ns]

0 2 4 6 8

Mas

s Flo

w(g

/min

)

Time (ms)

Test

Sim



12

0 2 4 6 8 10

Mas

s Flo

w(g

/min

)

Time(ms)

Test

Sim

Engine speed N1

Test bench and simulation results comparison for low pressure systemP1 pressure

0 2 4 6 8 10

Mas

s Flo

w(g

/min

)

Time(ms)

Test

Sim

0 2 4 6 8

Mas

s Flo

w(g

/min

)

Time (ms)

Test

Sim

P2 pressure

Engine speed N2

Engine speed N1

Engine speed N2




2 Modeling approach



5 Summary

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DoE case set up

The goal of DoE is to identify the most

probable combination of the design

parameters, which provide maximum flow

The available maximum design parameter

values are used as boundary condition

A full factorial DoE type is used for DoE

settings

Parameters Min Max

No. of Holes 4 12

Hole Dia mm 0.2 1

Sac Volume mm^3 1.18 7

Lift microns 60 100



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DOE case setup results

2.5ms On time




2 Modeling approach



5 Summary

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17

Summary

Sensitivity analysis shows that the model is able to capture the flow

dynamics under varying operating conditions.

The supply pressure is varied during static and dynamic conditions and

compared with actual test bench measurements.

The low pressure system operation is well captured in the simulation

and test bench comparison results show a good match

DOE analysis provide the best possible combination of the design

parameters with given constraints

GT 1D hydraulic simulation helps in reducing the number of prototype

generated, testing time, cost and effort



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I would like to Thank the following people for their help during this work Pradeep R (GS/ESB11-IN) – RBIN

Shawn Harnish – Gamma Technologies

Bradford Lynch – Gamma Technologies



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