development of a dedicated range extender unit and demo

Organized by Hosted by In collaboration with Supported by

Development of a Dedicated Range

Extender Unit and Demo Vehicle

Mike Bassett, Jonathan Hall and Marco Warth

MAHLE Powertrain Limited, UK


Contents

• Introduction

• Range Extender UnithSpecifications

hSystem Efficiency

• MAHLE Range Extender Demonstrator VehiclehTargets

hComponent Selection and Packaging

hControl Architecture

hREx Operating Strategy

h Initial Test Results

• Summary


3

Electric Vehicle (EV)

• Vehicle propelled by electric motors

• On-board battery pack sole energy source

• Range currently typically 80 to 250 km

• Charged from residential electrical outlet

Introduction - 1


4

Range Extended Electric Vehicle (REEV)

• Vehicle propelled by electric motors

• Battery pack downsized

• Typical battery only range of 20 to 100 km

• Charged from residential electrical outlet

• On-board generator re-charges battery

• Typically IC engine coupled to generator

• Used whilst vehicle moving

2013-01-1469

Introduction - 2


5

• Battery provides load-levelling of driver demand

• REx power requirement depends on battery size

– No battery – REx must provide instantaneous power

– Limitless battery – REx not required30 kW mechanical

power

Electric range

RE

xP

ow

er

/ Ta

il-p

ipe

CO

2

Ve

hic

le w

eig

ht

an

d c

ost

Range Extender - Power


6

• 0.9 litre, In-line 2-cylinder, Four-stroke, Gasoline

• 30 kW peak power at 4000 rev/min

• Port-fuel injection (λ = 1)

• 0°/180° TDC firing angles

• Flexible installation angle

• Fully integrated generator

• Euro 6 Emissions compliant

Specifications Summary


7

Dimensions

• L x W x Height: 416 x 327 x 481 mm

• Volume (Box): 65 litres

Size, Weight & Cost Optimised


8

• REx unit efficiency (engine + generator + invertor)

+ +

Complete System Efficiency

IME

P (bar)

0

2

4

6

8

10

12

Engine speed (rev/min)

1000 1500 2000 2500 3000 3500 4000 4500

3030

29

28

27

27

25

25

26

26

2424

Efficiency ηηηη total % Maximum IMEP

31 %


9

Lightweight and Compact Package Concept

• No primary out of balance forces (0°/180° firing)• No balancer shaft required

• Two bearing crankshaft• Low cost and low friction

• Flywheel located between cylinders• Small package volume

• Low rotational inertia

• Challenge: Cyclic speed fluctuations

Dynamic Generator Control


10

Torq

ue (N

m)

-600

-400

-200

0

200

400

600

800

Crank angle (°)

-360 -180 0 180 360

Total Engine

Uneven Torque Profile

• 0°/180° firing

• All torque from single crank revolution

• No torque from other revolution

Cyclic Torque Variation(2000 rev/min, 8 bar BMEP)



11R

ela

tive g

enera

tor to

rque (-)

0

1

2

Crank angle (°)

-360 -180 0 180 360

Engin

e s

peed (re

v/m

in)

1200

1400

1600

1800

2000

2200

2400

Crank angle (°)

-360 -180 0 180 360

Constant torque control

Speed Fluctuation

• Constant generator torque:

• ±400 rev/min speed fluctuation

Low cranktrain inertia � high speed fluctuation



12R

ela

tive g

enera

tor to

rque (-)

0

1

2

Crank angle (°)

-360 -180 0 180 360

Engin

e s

peed (re

v/m

in)

1200

1400

1600

1800

2000

2200

2400

Crank angle (°)

-360 -180 0 180 360

Constant torque control

Dynamic Control



Solution � Dynamic Generator Control



13R

ela

tive g

enera

tor to

rque (-)

0

1

2

Crank angle (°)

-360 -180 0 180 360

Engin

e s

peed (re

v/m

in)

1200

1400

1600

1800

2000

2200

2400

Crank angle (°)

-360 -180 0 180 360

Constant torque control Dynamic torque control

Dynamic Control



• Dynamic generator torque:

• Reduced speed fluctuation down to

±200 rev/min

• Smoother engine operation

• No large flywheel requirement



14

Peak a

ccele

ration (g)

0.00

0.25

0.50

0.75

1.00

1.25

1.50

Frequency (Hz)

0 50 100 150 200 250 300

Difference

Peak a

ccele

ration (g)

0.00

0.25

0.50

0.75

1.00

1.25

1.50

Frequency (Hz)

0 50 100 150 200 250 300

Constant torque Dynamic torque

Dynamic Generator ControlMeasurement Axis

Difference between the measured peak accelerations in

Dynamic and Constant generator control modes

Measured peak accelerations in Dynamic and Constant

generator control modes

(2000 min-1, 50% load)


15

Vehicle Concept

• Range Extended Electric Vehicle (REEV)

• Plug-in series hybrid

• Compact class

• Packaging challenge!

Demonstrator Vehicle


16

Parameter Units Base Vehicle REEV

0-100 km/h acceleration time s 11.7 12.0

Maximum speed km/h 180 145

Grade ability % _ 20

Maximum speed on 6 % grade km/h _ 90

Pure EV range km _ > 60

NEDC CO2 g/km 118 < 45

Vehicle Targets

Parameter Units Base Vehicle

0-100 km/h acceleration time s 11.7

Maximum speed km/h 180

Grade ability % _

Maximum speed on 6 % grade km/h _

Pure EV range km _

NEDC CO2 g/km 118

Demonstrator Vehicle


17

• Water cooled Li-Ion battery pack

• 14 kWh capacity

• 350 V nominal

• Integrated BMS

• Under boot floor installation

Battery Installation


18

• 55 kW (100 kW peak) traction motor

• 2-speed transmission

Drive-line Installation


19

PDU

VCU

Fuel Tank

CAN Bus

Mechanical

Connection

Fuel Line

HV Electrical

Connection

ECU: Engine Control Unit, VCU: Vehicle Control Unit, PDU: Power Distribution Unit

Range

ExtenderECU

Generator + Inverter

2-Speed Transmission

Traction Motor

+ Inverter

Battery

Charger

Control Architecture


20

IME

P (bar)

0

2

4

6

8

10

12


1000 1500 2000 2500 3000 3500 4000 4500

3030

29

28

27

27

25

25

26

26

2424

Maximum IMPE (bar) Efficiency (%)

• REx Efficiency

Operating Strategy


21

IME

P (bar)

0

2

4

6

8

10

12


1000 1500 2000 2500 3000 3500 4000 4500

24 24

26

26

25

25

27

27

28

29

3030

200200

500

400

300

Maximum IMPE (bar) Efficiency (%) Speed fluctuation (min-1)

• REx Efficiency

• NVH

• Speed

fluctuations

Operating Strategy


22

IME

P (bar)

0

2

4

6

8

10

12


1000 1500 2000 2500 3000 3500 4000 4500

25

1015 20

5

3030

29

28

27

27

25

25

26

26

2424

300

400

500

200200

Maximum IMPE (bar) Efficiency (%) Speed fluctuation (min-1) Mechanical power conturs (kW)

• REx Efficiency

• NVH

• Speed

fluctuations

Operating Strategy

Efficiency

compromise for

reduced NVH


23

IME

P (bar)

0

2

4

6

8

10

12


1000 1500 2000 2500 3000 3500 4000 4500

5

201510

25

24 24

26

26

25

25

27

27

28

29

3030

200200

500

400

300

Maximum IMPE (bar) Efficiency (%) Speed fluctuation (min-1) Mechanical power conturs (kW) Variable REx operating strategy

REx catalyst light-off operating point

• REx Efficiency

• NVH

• Speed

fluctuations

• Operating line of

best compromise

Operating Strategy


24

Pow

er (k

W)

0

5

10

15

20

25

30

35

40

Vehicle speed (km/h)

0 20 40 60 80 100 120 140

Range e

xte

nder speed (re

v/m

in)

0

1000

2000

3000

4000

Road power REx power REx engine speed

• Deplete battery

• Maximise EV range

• Load follow

• SOC sustaining

• Engine speed/load follows vehicle

speed

• Minimise noise and fuel

consumption

• Vehicle noise masks REx

• REx off at low vehicle speeds

• Unless SOC critically low

Operating Strategy


25

Battery

SO

C [%

] / R

Ex p

ow

er

[kW

]

0

5

10

15

20

25

30

Time [s]

0 200 400 600 800 1000 1200

Vehic

le s

peed [km

/h]

0

20

40

60

80

100

120

140

Battery SOC REx power Vehicle speed

• Depleted battery test conducted

• Some recharging of battery

occurred

• Strategy could be further refined

• R101 CO2 42 g/km

67 km EV range

430 km Extended range

~500 km Combined range

REx operation and battery SOC during NEDC

test

Initial Test Results


26

• Compact and light weight REx unit developed

• Plug-in series hybrid drive train system

integration and vehicle conversion

• Fully-fledged B-segment REEV demonstrator

vehicle with 500 km range and 42 g/km CO2

Summary


27

Thank you

development of a dedicated range extender unit and demo

Documents