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
2
4Evolving Design: Dieselmotoren
Geschiedenis lesje…
5Evolving Design: Dieselmotoren
2.“Grote diesels”
6Evolving Design: Dieselmotoren
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)
4
10Evolving Design: Dieselmotoren
High speed diesel engine
11Evolving Design: Dieselmotoren
11
12Evolving Design: Dieselmotoren
12
5
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
6
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
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
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
9
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
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
11
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 =
12
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
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⋅=
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
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?
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
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
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
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
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…
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
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
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
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