design & development of e-turbotm for suv and light truck … · 2014. 3. 11. · e-turbo™:...

Design & Development of e-TurboTM for SUV and Light Truck Applicaitons

S. M. ShahedChris Middlemass

Craig BalisGarrett Engine Boosting Systems

Diesel Engine Emissions Reduction Conference

August, 2003

Presentation OutlinePresentation OutlinePresentation Outline

• Preliminary System Benefits Quantified & Configuration Identified

• “Go/No-Go” Technical Feasibility Established• System Modeling Tools for EBS have been

Developed• Sensitivity Analysis has been Performed to Set

Development Targets• Key Technical Targets and Challenges have been

Defined• Feasible Technical Solutions have been Identified• Conclusions and Next Steps

Presentation includes gasoline and diesel engine data and analysisIt also includes e-Charger and e-Turbo results

e-Turbo™: Electrically-Assisted TurbochargerThree Levels of System Benefits

• Performance - Eliminate Turbolag

• Aggressive Engine Downsizing

• Air Management System - Synergy with EGR, Fuel Injection, Aftertreatment, Vehicle Power Demands

M/G - Supplier Developed 12 V DC Input 2 kW Induction Motor/GeneratorController - Supplier Developed

VEN - Vehicle Electric Network

C T

AirFilter

- TM

CAC

Controller ECU

VEN

Air Filter

C T

M/Ge-TurboTM

CAC

Exhaust

Controller ECU

VEN

Electronic Boosting Systems

Problem Statement for EBSProblem Statement for EBSProblem Statement for EBS

Tran

sien

t Tor

que

TimePedal step

Downsized turbocharged engine

Larger normally aspirated engine

Performance Benefits – Transient TorquePerformance Benefits Performance Benefits –– Transient TorqueTransient Torque

Transient torque with EBS

Pedal steptime

Steady state torquew/o EBS

Transient torquew/o EBS

Transient torque with EBS

Transient Time-to-Boost Improvement

Torq

ue

Temporary OverboostPedal step

time

Torq

ue

Steady state torquew/o EBS

Transient torquew/o EBS

Temporary overboostW/ EBS

Example of Benefits - Engine Test Results

0

50

100

150

200

250

300

350

500 1500 2500 3500 4500 5500 6500Engine Speed [RPM]

Torq

ue [N

m]

3.0L NA

1.8L T/C

1.8L T/C w/ EBS (e-Charger)

Transient Time-to-Boost Improvement

Temporary Overboost0

1

2

3

4

5

6

1000 1200 1400 1600 1800

Engine Speed [RPM]

Tim

e to

Boo

st [s

]

baseline w/o EBS

with EBS (e-Charger)

Reference: baseline steady state

• In-House Design e-Charger• Permanent Magnet System• 1.8 L European Gasoline

Engine• Testing at European

Consultancy

Proof of Concept Using e-Charger and

Gasoline EngineGarrett in-house design e-Charger

with Permanent Magnet Motor and In house controller

% FC Improvement

0

4

8

12

16

20

0 5 10 15 20 25 30 35% Capacity Downsize%

Fue

l Con

sum

ptio

n Im

prov

emen

t

Opel 2.2 - 2.0

Renault 1.9 - 1.5

Alfa Romeo 2.4 - 1.9

New Polo 1.9 I4 - 1.4 I3

Old Polo 1.9 I4 - 1.4 I3

IL4 1.9 - 1.7Peugeot 2.0 - 1.4

Diesel Engine Turbocharging & DownsizingDiesel Engine Turbocharging & DownsizingDiesel Engine Turbocharging & Downsizing

EuropeanProduction ModelsSame Vehicle

10-30% Downsizing6-17% Fuel Economy Improvement

Effect of Downsizing on Fuel Consumption

Engine Capacity (litres)

Fuel

Con

sum

ptio

n (l/

100k

m)

4.0

4.5

5.0

5.5

6.0

6.5

7.0

1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

Renault 1.9-1.5

Opel 2.2-2.0

Alfa Romeo 2.4 - 1.9

IL4 1.9-1.7PSA 2.0-1.4

VW 1.9-1.4Opel

2.0-1.

7

Credits

Gasoline Engine Downsizing & TurbochargingGasoline Engine Downsizing & Turbocharging

• Units litres/100 km - lower is better• Turbocharged downsized engines show 8-10%

better fuel economy than non-turbochargedengines over 10 years of production vehicles

Fuel Economy MY 1992Fuel Economy MY 1992--9393

Fuel Economy MY 2000 Fuel Economy MY 2000 --0101

Fuel Economy MY 2002 Fuel Economy MY 2002 --0303

NA TC Linear (TC) Linear (NA)

8

9

10

11

12

13

100 120 140 160 180

Rated Power kW

Fuel

Con

s L/

100

km

8

9

10

11

12

13

14

100 120 140 160 180

Rated Power kW

Fuel

Con

s (L

/100

km

)

8

9

10

11

12

13

100 120 140 160 180

Rated Power kW

Fuel

Con

s (L

/100

km

)

Critical “Go/No-Go” Technical Feasibility CriteriaCritical Critical ““Go/NoGo/No--GoGo”” Technical Feasibility CriteriaTechnical Feasibility Criteria• High-speed motor/controller system to provide up to

1.4kW mechanical power at speeds up to 175kRPM total system efficiency > 70%.

• Turbocharger bearing system to carry the extra mass and length while still retaining acceptable shaft rotor-dynamic behavior up to 225kRPM.

• Turbocharger and motor cooling system to protect the motor from the extreme turbocharger thermal environment as well as from self-heating.

• Compressor aerodynamics to deliver the extra boost without suffering from surge (“stall”) during the transient.

Designs Successfully Establish Feasibility

Modeling tools

EBS control strategies

development

EBS system analysis, specification and

optimization

EBS matching for specific customer

application

Modeling for EBSModeling for EBSModeling for EBS

High level to low level specification

Componentspecification

Systemmodel

System performance target

(customer input)

Subsystemsspecification

Component model

e.g. electric motor torque curve

e.g. winding spec., rotor spec., ...

e.g. motor model

EBS System AnalysisEBS System AnalysisEBS System Analysis

Engine mean value model (diesel and gasoline)

• Thermodynamics/mechanical model of turbocharged engine

• Validated against steady state and transient engine data

System Model SchematicSystem Model SchematicSystem Model Schematic

Turbochargedengine+ EBS

EngineManagement

SystemVehicle

Sensors

Actuators

System Model: Matlab/Simulink ImplementationSystem Model: System Model: MatlabMatlab//Simulink Simulink ImplementationImplementation

Engine

Compressor

Turbine

Charge Air Cooler

AirFilter

Exhaustline

Tamb = 20°C

Pamb=1000 mbar

Throttle(if applicable)

Fixed outlet temperatureduring transient TCAC = 35°C(thermal inertia)

Actuator dynamic: τ = 70 ms

• Efficiency correction for pulse effect (WG turbine)• Actuator dynamic: τ = 70 ms

• BSFC, volumetric, thermal and indicated efficiencies kept to steady state full load values

• No knock effect considered

Summary of Main Modeling AssumptionsSummary of Main Modeling AssumptionsSummary of Main Modeling Assumptions

During transient simulation:Goal: Reach & Maintain Boost Pressure Set Value• Throttle (if applicable) Control:

Fast opening at PPS step (instantaneous 100 % DC command)• WG/VNT Control:

Open at part load (0% DC command)Fast closing at PPS step (instantaneous 100 % DC command)Kept closed if electric motor activated, regulation mode afterward

• Electric Motor Control: Fast starting at PPS step (instantaneous 100 % DC command)Regulation mode afterward

• Boost Pressure Set Value:If EBS is activated, desired boost pressure set to maximum full load boost

PPS-Pedal Position SensorWG for Gasoline and VNT for Diesel


0

200

400

600

800

1000

1200

0 1000 2000 3000 4000 5000 6000

Engine Speed [RPM]

Des

ired

Boo

st P

ress

ure

(Ful

l loa

d) [k

Pa]

Boost pressure set value with EBS

Boost pressure set value w/o EBS


P2c [mbar]

0

200

400

600

800

1000

1200

1400

0 200 400 600 800 1000 1200 1400Engine data

Mod

el

Engine delta P [mbar]

-1000

-800

-600

-400

-200

0

200

400

-1000 -800 -600 -400 -200 0 200 400Engine data

Mod

el

T2c [°C]

20

40

60

80

100

120

140

160

20 40 60 80 100 120 140 160Engine data

Mod

el

Engine Torque [Nm]

0

50

100

150

200

250

300

0 50 100 150 200 250 300Engine data

Mod

el

Steady-State Model ValidationSteadySteady--State Model ValidationState Model Validation

• 1600 kg vehicle - 2.0L gasoline engine (e-Turbo OFF)• Acceleration in 4th gear from 1000 RPM — model

— engine data

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Boo

st P

ress

ure

[kPa

]

0

40000

80000

120000

160000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Turb

o S

peed

[kph

]

0

1000

2000

3000

4000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Engi

ne S

peed

[RP

M]

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Veh

icle

Spe

ed [k

ph]

Boost pressureTurbochargerspeed

Engine speed Vehicle speed

Transient Model ValidationTransient Model ValidationTransient Model Validation

• 1600 kg vehicle - 2.0L engine (e-Turbo ON)• Acceleration in 4th gear from 1000 RPM — model

— engine data

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Boo

st P

ress

ure

[kPa

]

0

40000

80000

120000

160000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Turb

o S

peed

[kph

]

0

1000

2000

3000

4000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Engi

ne S

peed

[RP

M]

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Veh

icle

Spe

ed [k

ph]

Boost pressureTurbochargerspeed

Engine speed Vehicle speed


1600 kg vehicle - 2.0L gasoline engine• Acceleration in 4th gear from 1000 RPM

— model— engine data

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Boos

t Pre

ssur

e [k

Pa]


0

50

100

150

200

250

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Boos

t Pre

ssur

e [k

Pa]

(e-Turbo OFF)

(e-Turbo ON)

1600 kg vehicle - 2.0L gasoline engine• Acceleration in 4th gear from 1000 RPM

— model— engine data

0

40000

80000

120000

160000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Turb

o Sp

eed

[kph

]Transient Model ValidationTransient Model ValidationTransient Model Validation

(e-Turbo OFF)

0

40000

80000

120000

160000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15t [s]

Turb

o Sp

eed

[kph

](e-Turbo ON)

• Fixed RPM ramp after load step (400 engine RPM/s)• Electric motor mechanical power: 1250 W• Relative value compared to transient w/o EBS• Diesel Engine Modeling - % increase in torque in ~ 1 sec

Transient torque increase over “no-EBS value” in ~ 1 sec

0

10

20

30

40

50

60

1000 1200 1400 1600 1800 2000Engine Speed [RPM]

Torq

ue in

crea

se [%

]

1.4L2.0L2.6L3.2L

EngineRPM

time

Load step

Sensitivity Analysis Example: DisplacementSensitivity Analysis Example: DisplacementSensitivity Analysis Example: Displacement

Logic for using speed ramp

• Fixed RPM ramp after load step (400 engine RPM/s)• Relative value compared to transient w/o EBS• Diesel Engine Modeling - % increase in torque in ~ 1 sec

Transient torque increase over “no-EBS value” @ 1500 RPM

0

10

20

30

40

50

60

1.4 2 2.6 3.2

Engine Displacement [L]

Torq

ue in

crea

se [%

]

750 W1000 W1250 W1500 W

Sensitivity Analysis Example: PowerSensitivity Analysis Example: PowerSensitivity Analysis Example: Power

Logic for using speed ramp

Key Technical Challenges and Targets (2.0L)Key Technical Challenges and Targets (2.0L)Key Technical Challenges and Targets (2.0L)

• Maintain baseline turbocharger speed = 225kRPM– Challenge for rotor bearing subsystem to carry motor

Extra length of shaftOverhung weight of motor

– Challenge for motor mechanical stressDurability at high speed

• Motor performance– Acceptable performance on 12V network and < 2kW electric input

Torque and mechanical power necessary for boost benefitEfficiency to minimize electric input power requirement

• Compressor aerodynamics to deliver full benefits of motor boost– Good efficiency at low flow, low pressure ratio– Good range to avoid surge during overboost

• Temperature capability and cooling: motor < 180C• Protection of motor at severe “off” conditions (e.g. soakback)

– Unconstrained duty cycle operation at typical operating conditions– Partial duty cycle operation at worst-case operating conditions

850C turbine inlet110C cooling water150C oil temperature

Solutions Require Integrated ApproachSolutions Require Integrated ApproachSolutions Require Integrated Approach

e-Turbo Design Parameters

Turbocharger Size

Motor M

echanical Speed Lim

it

Com

pressor Range/S

urge

Motor Torque

Rotor D

iameter

Bearing Type

Rotordynam

ic Stability

Shaft M

otion

Bearing Length

Bearing D

iameter

Rotor/S

tator Air G

ap

Motor Length

Oil S

ystem

Cooling S

ystem

Motor E

fficiency

Motor P

ower

Stator D

iameter

Com

pressor Packaging

Motor M

otoring Speed Lim

it

Turbine Packaging

Turbocharger SizeMotor Mechanical Speed LimitCompressor Range/SurgeMotor TorqueRotor DiameterBearing TypeRotordynamic StabilityShaft MotionBearing LengthBearing DiameterRotor/Stator Air GapMotor LengthOil SystemCooling SystemMotor EfficiencyMotor PowerStator DiameterCompressor PackagingMotor Motoring Speed LimitTurbine Packaging

Rotor Bearing SubsystemRotor Bearing SubsystemRotor Bearing Subsystemy

S ynchronous L im itTota l M otion L im itS YN EATTO TAL EATS YN e -Turbo sca le d Z be a ringTO TAL e -Turbo sca le d Z be a ringS YN e -Turbo Ba ll Be a ringTO TAL e -Turbo Ba ll Be a ring

Earlier design stability issue

Current e-Turbo design stable above

target speed

• 5 Bearing systems defined• Downselection to 3 systems for testing• 3 systems successfully testing:

• 2 journal bearing (Z bearing)• 1 ball bearing

Turbocharger Speed

Shaf

t Mot

ion

Cooling SubsystemCooling SubsystemCooling SubsystemMountain Route

0

10

20

30

40

1 2 3 4 5 6 7Time [sec]

Tota

l Occ

uran

ces

[%]Vehicle Duty-Cycle Recording @ Several Conditions

Statistical Analysis

3D Transient Thermal Modeling to Optimize Cooling

30

50

70

90

110

130

0 200 400 600 800 1000 1200Time (sec)

Tem

pera

ture

(°C

)

Good Temperature Margin at Normal Conditions

e-Turbo Bench Test and Model Validation at Mountain Duty Cycle Conditions

0 50 100 150 200 250 300 350 400 450 500

Time [s]

ON

/OFF

190

130

140

150

160

170

180

0 5 10 15 20 25 30 35 40 45 50

Operation Still Possible at Worst-Case Conditions

Rotor max temperatureStator max temperature

Tem

pera

ture

(°C

)

City Mountain Highway Country RoadDuty Cycle (%) 7% 19% 3% 6%

Average ON time (sec) 1.1 2.2 1.5 1.3% ON > 2 sec 91% 58% 83% 86%

Conclusions and Next StepsConclusions and Next StepsConclusions and Next StepsConclusions• System models have been developed, validated, and used

to set development targets• Testing and simulation has validated the potential for

engine downsizing using EBS• Key technical challenges have been identified and

solutions have been found: rotor bearing subsystem, cooling system, motor, aerodynamics

• Next Steps• Develop next-generation prototype encompassing latest

technical solutions and performance targets• Perform engine and vehicle testing to validate

performance and downsizing potential• Assess total installed system cost and packaging• Scale up to SUV Size Engine

design & development of e-turbotm for suv and light truck … · 2014. 3. 11. · e-turbo™:...

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