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Page 1: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

1

31-5-2011

Challenge the future

DelftUniversity ofTechnology

wb3110 Combustion Engines Evolving design in marine propulsion

Dr. Hugo Grimmelius

2Evolving Design: Dieselmotoren

1.Introduction: history

3Evolving Design: Dieselmotoren

Tijdschaal

• Eind 1600 eerste experimenten met stoom• 1816 het stirling principe• 1880 eerste gasmotor.• 1886 Otto motor op benzine• 1892 Diesel zelfontbranding• 1957 Wankelmotor

Page 2: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

2

4Evolving Design: Dieselmotoren

Geschiedenis lesje…

5Evolving Design: Dieselmotoren

2.“Grote diesels”

6Evolving Design: Dieselmotoren

Page 3: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

3

7Evolving Design: Dieselmotoren

Slow speed engine (2 stroke)

8Evolving Design: Dieselmotoren

8

Medium speed engine (line)

9Evolving Design: Dieselmotoren

9

Medium speed engine (V)

Page 4: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

4

10Evolving Design: Dieselmotoren

High speed diesel engine

11Evolving Design: Dieselmotoren

11

12Evolving Design: Dieselmotoren

12

Page 5: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

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13Evolving Design: Dieselmotoren

13

14Evolving Design: Dieselmotoren

3.Theorie

15Evolving Design: Dieselmotoren

Cilinder geometrie

TDCV

VBDC

TDC

BDC

SLStroke:

BDBore:

S2

B

SBS

LD4

LAV

⋅⋅π=

⋅=Stroke volume:

TDC

BDC

VV=ε

Geometricalcompression ratio:B

SS D

L=λStroke-bore

ratio

Page 6: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

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16Evolving Design: Dieselmotoren

4-takt principe

rotation

crank

piston

exhaust valveinlet valve

cylinder

connecting rod

fuel injector

DA B C

17Evolving Design: Dieselmotoren

2-takt principe

inlet port

DA B C

piston rod

crosshead

connecting rod

piston

fuel injector

exhaust valve

cylinder

crank

rotation

18Evolving Design: Dieselmotoren

Scavenging

A B

"Uni-flow" scavenging "Loop" scavenging

Page 7: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

7

19Evolving Design: Dieselmotoren

p-V diagram

61

5

2

3 4

V

VSVTDC

p

VBDC

V

VSVTDCVBDC

2

3 4

5

6

1

p

A) 4-stroke cycle B) 2-stroke cycle

20Evolving Design: Dieselmotoren

Standard air cycles

• Closed cycle• Combustion: external heat input• Perfect gas:

• All processes internally reversible• Compression and expansion isentropic, i.e. reversible and en

adiabatic, so Poisson applicable:

• Expansion ends in same point where compression starts

p V m R T⋅ = ⋅ ⋅ pc constant=

v pc c -R constant= =

1T V constantκ−⋅ =

p V constantκ⋅ =p

v

cc

constantκ = =

21Evolving Design: Dieselmotoren

Otto cycle

p

v

T

s

s=c

s=c

v=c

v=c

2

3

4

11

2

3

4

Page 8: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

8

22Evolving Design: Dieselmotoren

Diesel cycle

1

2 3

4

1

2

3

4

s=c

s=c

p=c

v=c

p

v s

T

23Evolving Design: Dieselmotoren

Seiliger (dual) cycle

2

3 4

5

11

2

3

4

5

T

sv

p

s=c

v=c

v=c

p=c

s=c

24Evolving Design: Dieselmotoren

Turbocharger

ExhaustReceiverexh

Principle of turbocharging

Cylinders

inlInletReceiver

Charge AirCompressor

Inlet Filter

IC Intercooler

Exhaust GasTurbine

Exhaust Silencer

Page 9: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

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25Evolving Design: Dieselmotoren

Limits in engine characteristic

max rpm

Min power

Engine speed (rpm)

Enginepower(kW)

Max power

min rpm

26Evolving Design: Dieselmotoren

Real envelope natural aspirating engine

PB

ne,min ne,max ne

MB

ne,min ne,max ne

27Evolving Design: Dieselmotoren

Real engine envelopes

Page 10: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

10

28Evolving Design: Dieselmotoren

Principle of indicated work

BDC

TDC

V

exp expV

W p dV= ⋅∫Expansion stroke delivers work:

TDC

BDC

V

comp compV

W p dV= ⋅∫Compressions stroke requires work:

i exp compcycle

W W W p dV= + = ⋅∫

Total indicated work is net sum:

< 0 (since dV <0!!)

29Evolving Design: Dieselmotoren

Mean indicated pressure

W p dV p Vi

rev

cycleS= ⋅ = ⋅∫

The indicated work as measured in a p-V diagram:

pWVmi

defi

S

=So the mean indicated pressure (MIP)also:

indicated mean effective pressure (imep)State-of-the-art: 20 to 33 bar

S

cycledef

Vk2

dVpp

⋅⋅

⋅=∫

Mathematically a mean value can be defined: 2-stroke: k=14-stroke: k=2

Technically it is more practical to relate indicated work just to the stroke volume

30Evolving Design: Dieselmotoren

Mean effective pressure

ηm

def e

i

WW

= Mechanical losses:

pWVme

defe

S

=Define the mean effective pressure (MEP)also:

brake mean effective pressure (bmep)State-of-the-art: 15 – 30 bar

mimme pp ⋅η=So:

pWVmi

defi

S

=Compare (MIP)

∫⋅π

α⋅⋅=k2

0flange

def

e dMi1W

The effective work as measured at the output flange:

i = nr of cylinders

Page 11: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

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31Evolving Design: Dieselmotoren

Connection with brake power

en ifk⋅

=

Firing frequency:

P W fB e= ⋅

Power iswork per second:

eS

i nV Vk⋅

= ⋅recognize nominal volume flow

through engineSo mean effective pressure is

specific power of a volumetric machine

Bme

e S

Pp k i n V

= ⋅⋅ ⋅

defe e

B e me Sn i n iP W p V

k k⋅ ⋅= ⋅ = ⋅ ⋅

pWVme

defe

S

=

32Evolving Design: Dieselmotoren

Connection with brake torque

Bme

e S

Pp k i n V

= ⋅⋅ ⋅

def

B B eP M 2 n= ⋅ π⋅

Power is torque times speed

So mean effective pressure is torquescaled with total swept volume

Bme

S

Mp 2 k i V

= π⋅ ⋅⋅

33Evolving Design: Dieselmotoren

Power density

Cluster the formula for mean effective pressure as follows:

S

B

eme Vi

Pnkp

⋅⋅=

Then power related to total engine cylinder displacement is:

BVS

S

Pi V

β =⋅

Conclusion for high power density:- High speed

- High mean effective pressure- 2-stroke instead of 4-stroke !!?

me eVS

p nk⋅

β =

Page 12: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

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34Evolving Design: Dieselmotoren

Trend of power / stroke volume as function of nominal speed

Specific power related to swept volume

0

10

20

30

40

50

0 400 800 1200 1600 2000 2400

Nominal engine speed in rpm

Pow

er/c

yl v

ol in

kW

/ltr

High speed 4-stroke V-engines

High/medium speed 4-stroke Line-engines

High/medium speed 4-stroke V-engines

Medium speed 4-stroke Line-engines

Medium speed 4-stroke V-engines

Low speed 2-stroke Line engines

35Evolving Design: Dieselmotoren

Trend of weight specific poweras function of nominal speed

Weight specific power

0.000

0.100

0.200

0.300

0.400

0.500

0 400 800 1200 1600 2000 2400

Nominal engine speed in rpm

Wei

ght s

peci

fic p

ower

MW

/ton

High speed 4-stroke V-engines

High/medium speed 4-stroke Line-engines

High/medium speed 4-stroke V-engines

Medium speed 4-stroke Line-engines

Medium speed 4-stroke V-engines

Low speed 2-stroke Line engines

36Evolving Design: Dieselmotoren

Trend of volume specific poweras function of nominal speed

Volume specific power

0.000

0.100

0.200

0.300

0.400

0.500

0 400 800 1200 1600 2000 2400

Nominal engine speed in rpm

Volu

me

spec

ific

pow

er M

W/m

3

High speed 4-stroke V-engines

High/medium speed 4-stroke Line-engines

High/medium speed 4-stroke V-engines

Medium speed 4-stroke Line-engines

Medium speed 4-stroke V-engines

Low speed 2-stroke Line engines

Page 13: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

13

37Evolving Design: Dieselmotoren

Bore area & mean piston speed

Cluster the formula for mean effective pressure as follows:

B

B

Seme Ai

PLn

kp⋅

⋅⋅

= with: V L AS S B= ⋅

mme cp ⋅

“Technology”Introduce mean piston speed:

defS

m

e

2 Lc1

n

distancetime

⋅= = ⇒ m e Sc 2 n L= ⋅ ⋅

Low speed 2-stroke: approx. 8 m/sMedium and high speed 4-stroke: 9 –12 m/s

Then power related to total engine bore area is:

kLnp

AiP Seme

B

BAB

⋅⋅=⋅

=βk2cp mme

AB ⋅⋅=β

38Evolving Design: Dieselmotoren

Trend of technology parameter

Technology parameter Diesel Engines

0

100

200

300

400

0 400 800 1200 1600 2000 2400

Nominal engine speed in rpm

Tech

nolo

gy: p

e*cm

in b

ar *

m/s

High speed 4-stroke V-engines

High/medium speed 4-stroke Line-engines

High/medium speed 4-stroke V-engines

Medium speed 4-stroke Line-engines

Medium speed 4-stroke V-engines

Low speed 2-stroke Line engines

39Evolving Design: Dieselmotoren

Maximum power engine blockMaximum power is proportional to NR of cylinders, bore area

and “technology”; for 4-stroke divide by k = 2:

P i Ap c

kB Bme m= ⋅ ⋅

⋅⋅2

2e

2e

2S

2S

2B2

BB nnL

LD

4D

4A ⋅⋅⋅π=⋅π=

Bore area cannot be chosenarbitrarily:

For 4-strokebetween 1.1 and 1.5

Ratio Stroke/Bore: λS S BL D= /

Sem Ln2c ⋅⋅=Mean piston speed:

between 8 and 12 m/s!

2e

2S

2m

B n1c

16A ⋅

λ⋅π=

2e

2S

3mme

B n1

kcp

32iP ⋅

λ⋅⋅⋅π⋅=

Page 14: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

14

40Evolving Design: Dieselmotoren

Maximum power diesel engines

Maximum power obtainable from diesel engines

0

10

20

30

40

50

60

70

0 250 500 750 1000 1250 1500 1750 2000

Nominal speed in rpm

Max

imum

pow

er in

MW

Slow speed: 2-stroke, 12 cyl, pe = 18 bar, cm = 8 m/s, L/D = 3.5

41Evolving Design: Dieselmotoren

Maximum power diesel engines

Maximum power obtainable from diesel engines

0

10

20

30

40

50

60

70

0 250 500 750 1000 1250 1500 1750 2000

Nominal speed in rpm

Max

imum

pow

er in

MW

Slow speed: 2-stroke, 12 cyl, pe = 18 bar, cm = 8 m/s, L/D = 3.5

Medium speed:4-stroke, 16 cyl, pe = 24 bar, cm = 10 m/s, L/D = 1.3

42Evolving Design: Dieselmotoren

Maximum power diesel engines

Maximum power obtainable from diesel engines

0

10

20

30

40

50

60

70

0 250 500 750 1000 1250 1500 1750 2000

Nominal speed in rpm

Max

imum

pow

er in

MW

Slow speed: 2-stroke, 12 cyl, pe = 18 bar, cm = 8 m/s, L/D = 3.5

Medium speed:4-stroke, 16 cyl, pe = 24 bar, cm = 10 m/s, L/D = 1.3

High speed: 4-stroke, 20 cyl, pe = 30 bar, cm = 12 m/s, L/D = 1.1

Page 15: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

15

43Evolving Design: Dieselmotoren

Maximum power diesel engines

Power of Diesel Engines

0

10

20

30

40

50

60

70

80

90

0 400 800 1200 1600 2000 2400

Nominal engine speed in rpm

Pb in

MW

High speed 4-stroke V-engines

High/medium speed 4-stroke Line-engines

High/medium speed 4-stroke V-engines

Medium speed 4-stroke Line-engines

Medium speed 4-stroke V-engines

Low speed 2-stroke Line engines

44Evolving Design: Dieselmotoren

Three players in the game

3me m

B 2 2S e

p c 1P i32 k n

⋅π= ⋅ ⋅ ⋅⋅λ

Stroke/Boreratio

Meaneffectivepressure

Meanpistonspeed

45Evolving Design: Dieselmotoren

4.Wat kan er nog?

Page 16: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

16

46Evolving Design: Dieselmotoren

Trade-off between efficiency and specific work

20%

30%

40%

50%

60%

200 400 600 800 1000Specific work in kJ/kg

Cyc

le e

ffici

ency

SC

IC-RH2-HE

IC

IC-RH2

Trade-off between efficiency and specific work

20%

30%

40%

50%

60%

200 400 600 800 1000Specific work in kJ/kg

Cyc

le e

ffici

ency

SC

IC-RH2-HE DE

IC

IC-RH2

Introduction: comparison

47Evolving Design: Dieselmotoren

Introduction: assumptions

• Air-fuel ratio• Combustion parameters • Constant isentropic efficiencies:

• Compression and expansion in the cylinder• Turbocharger compressor and turbine

• Constant heat exchange efficiency• Heat input and mechanic efficiency

48Evolving Design: Dieselmotoren

Introduction: losses

Mechanical and heat input efficiency

70%

80%

90%

100%

2 3 4 5 6 7 8Charge air pressure ratio

(Par

tial)

effic

ienc

y in

% ηq

ηm

Page 17: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

17

49Evolving Design: Dieselmotoren

Introduction: scope

Investigation of:• Limits for:

• charge air pressure• maximum cycle pressure

• Ideal combustion process• Hot Combustion Diesel Engine

50Evolving Design: Dieselmotoren

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1969

1999

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

pimax = 800

pimax = 160

pimax = 220

pimax = 400

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

picharge = 1.5

picharge = 3

picharge = 5 picharge = 8

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

ε = 10

ε = 30

ε = 14

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

piscav = 1.3

piscav = 1.4

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1969

1999

Variation of π charge and π max

51Evolving Design: Dieselmotoren

60% overall efficiency

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

Constant bmep

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

Constant picharge

Trade-off betweenfuel economy and power density

35%

40%

45%

50%

55%

60%

65%

0 10 20 30 40 50 60Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

Constant ε

Page 18: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

18

52Evolving Design: Dieselmotoren

Efficiency vs max temperature

Comparison between efficiency and exhaust temperature

35%

40%

45%

50%

55%

60%

65%

1673 1923 2173 2423 2673 2923

Maximum cylinder temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999 picharge = 1.5

picharge = 8

pimax = 800

53Evolving Design: Dieselmotoren

Variation of π charge and π max

To reach 60% overall efficiency:• Significant increase in maximum pressure ratio• Either high charge air ratio• Or high compression ratio• Increase in maximum temperatures

54Evolving Design: Dieselmotoren

Trade-off between fuel economy and power density

44%

46%

48%

50%

52%

22 23 24 25 26Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

constant p = 1 (diesel)constant p = 1.5

constant p = 2

Varying combustion shape

Trade-off between fuel economy and power density

44%

46%

48%

50%

52%

22 23 24 25 26Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

constant T = 1

constant T = 2

constant T = 4

Trade-off between fuel economy and power density

44%

46%

48%

50%

52%

22 23 24 25 26Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

% 1999

Comparison between efficiency and maximum cylinder temperature

44%

46%

48%

50%

52%

1673 1873 2073 2273 2473Maximum cycinder temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

constant p = 1 (diesel)

constant T = 1

Comparison between efficiency and maximum cylinder temperature

44%

46%

48%

50%

52%

1673 1873 2073 2273 2473Maximum cycinder temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

Ideal diesel process

Page 19: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

19

55Evolving Design: Dieselmotoren

Varying combustion shapeT - s diagram for constant

volume combustion ratio 1.5

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant T combustion ratio = 3

T - s diagram for constant volume combustion ratio 1.5

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant T combustion ratio = 2

T - s diagram for constant volume combustion ratio 1.5

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant T combustion ratio = 1

T - s diagram for constant volume combustion ratio 1.5

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant T combustion ratio = 1

T - s diagram for constanttemperature combustion ratio 2

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant V combustion ratio = 2

T - s diagram for constant volume combustion ratio 1.5

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant T combustion ratio = 1

T - s diagram for constanttemperature combustion ratio 2

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant V combustion ratio = 1.5

T - s diagram for constant volume combustion ratio 1.5

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant T combustion ratio = 1

T - s diagram for constanttemperature combustion ratio 2

273

773

1273

1773

2273

2773

0.00 0.50 1.00 1.50

Specific entropy in kJ/kg/K

Abs

olut

e te

mpe

ratu

re in

K

constant V combustion ratio = 1

56Evolving Design: Dieselmotoren

Varying combustion shape

• Limited possibilities• High cylinder temperatures: emissions• Difficulties with residual fuel

57Evolving Design: Dieselmotoren

Hot Combustion Engine

Higher exhaust gas temperatures• Decrease of valve overlap• Increase in charge air temperature• Reduce heat losses in the cylinder during compression,

combustion and expansion• Allow higher wall temperatures• Reduce air fuel ratio

Page 20: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

20

58Evolving Design: Dieselmotoren

Trade-off between fuel economy and power density

46%

48%

50%

52%

54%

20 24 28 32Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

Hot Combustion Engine

Trade-off between fuel economy and power density

46%

48%

50%

52%

54%

20 24 28 32Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999charge air

valve overlap

Trade-off between fuel economy and power density

46%

48%

50%

52%

54%

20 24 28 32Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

heat loss

Trade-off between fuel economy and power density

46%

48%

50%

52%

54%

20 24 28 32Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

wall temperature

Trade-off between fuel economy and power density

46%

48%

50%

52%

54%

20 24 28 32Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

HCE

air-fuel ratio

Trade-off between fuel economy and power density

46%

48%

50%

52%

54%

20 24 28 32Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

HCE

heat loss = 0%

heat loss = 6%

Trade-off between fuel economy and power density

46%

48%

50%

52%

54%

20 24 28 32Brake mean effective pressure (bmep) in bar

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

HCE

air-fuel ratio = 2.2

air-fuel ratio = 1.6

59Evolving Design: Dieselmotoren

Hot Combustion Engine

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

valve overlap

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

charge air

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999heat loss

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

wall temperature

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

HCE

air-fuel ratio

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

HCE

heat loss = 0%

heat loss = 6%

Comparison between efficiency and exhaust temperature

46%

48%

50%

52%

54%

673 773 873 973 1073Exhaust temperature in K

Tota

l effi

cien

cy (e

ta-to

t) in

%

1999

HCE

air-fuel ratio = 2.2

air-fuel ratio = 1.6

60Evolving Design: Dieselmotoren

5.De toekomst…

Page 21: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

21

61Evolving Design: Dieselmotoren

Uitdagingen

• Emissie eisen• Low NOx: ‘koele’ verbranding of nabehandelen?• Low SOx: andere brandstof?

• Brandstofschaarste (prijs!)• Langzaam varen?• Andere brandstof?

• En natuurlijk:• Voor dezelfde prijs, ook voor onderhoud• Met minstens gelijke betrouwbaarheid

62Evolving Design: Dieselmotoren

Koele verbranding: Miller timing

• Gebruik deel van inlaatslag voor expansie• Inlaatklep sluit voor onderste dode punt!

• Voordeel: lucht aan begin compressieslag koeler• Nadeel: Verlies van effectief zuigervolume

• Oplossing: hoge vuldruk

63Evolving Design: Dieselmotoren

Two-stage turbocharging

LP Charge AirCompressor

Inlet Filter

IC LP Intercooler

Cylinders

inlInletReceiver

HP Charge AirCompressor

ICHP Intercooler

ExhaustReceiverexh

HP Exhaust GasTurbine

HPTurbocharger

LP Exhaust GasTurbine

LPTurbocharger

Exhaust Silencer

Page 22: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

22

64Evolving Design: Dieselmotoren

Andere brandstof

• Meestal lagere specifieke verbrandingswaarde

0 2 4 6 8 10 12

Diesel

Ethanol

Methanol

Ammonia, -32C, 8 bar

LNG

Hydrogen gas 700 bar

Liquid hydrogen

Volumetric specific energy content[kWh/liter]Gravimetric specific energy content[kWh/kg]

65Evolving Design: Dieselmotoren

Andere brandstof

• Meestal lagere specifieke verbrandingswaarde

• Well-to-tank implicaties?(emission versus impact)

66Evolving Design: Dieselmotoren

Andere brandstof: (L)NG?

• Natural gas (aardgas) is merendeel methaan (CH4)

• Methaan bevat de grootste hoeveelheid waterstof per hoeveelheid energieinhoud van alle fossiele brandstoffem

• Koolstof/waterstof mol ratio 1 / 4 (benzine: 1 / 2,25)

• Lagere CO2 emissies

• Natural gas is:• Niet giftig

• Kleurloos

• Reukloos

• Lichter dan lucht

Methane (CH4)

H

H

H HC

Page 23: 110525 wb3110 ED combustion engines - TU Delft OCW€¦ · • Compression and expansion in the cylinder • Turbocharger compressor and turbine • Constant heat exchange efficiency

23

67Evolving Design: Dieselmotoren

Dual Fuel

* **** ***

******

** *****

* *

Intake ofair and gas

Compression ofair and gas

Ignition bypilot diesel fuel

Otto principle

Low-pressure gas admission

Pilot diesel injection

Gas mode: Ex. In. Ex. In.Ex. In.

Intake ofair

Compression ofair

Injection ofdiesel fuel

Diesel principle

Diesel injection

Diesel mode:Ex. In. Ex. In.Ex. In.

68Evolving Design: Dieselmotoren

6.Afsluiting