Xin Q. Diesel Engine System Design
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962 Diesel engine system design
© Woodhead Publishing Limited, 2011
Turbine effective area (cm
2
)
BSFC (lb/(hp.hr))
Engine delta P (mbar)
Lumped EGR circuit flow coefficient
Overall turbocharger efficiencyOverall turbocharger efficiencyOverall turbocharger efficiency
Overall turbocharger efficiency
Overall turbocharger efficiency
Overall turbocharger efficiency
0.56
0.55
0.54
0.53
0.52
0.51
0.5
0.49
0.48
0.47
0.46
0.56
0.55
0.54
0.53
0.52
0.51
0.5
0.49
0.48
0.47
0.46
0.56
0.55
0.54
0.53
0.52
0.51
0.5
0.49
0.48
0.47
0.46
0.56
0.55
0.54
0.53
0.52
0.51
0.5
0.49
0.48
0.47
0.46
0.56
0.55
0.54
0.53
0.52
0.51
0.5
0.49
0.48
0.47
0.46
0.56
0.55
0.54
0.53
0.52
0.51
0.5
0.49
0.48
0.47
0.46
0.425
0.42
0.415
0.41
0.405
0.4
0.395
0.39
0.3
0.28
0.26
0.24
0.22
0.2
0.18
6.6
6.4
6.2
6
5.8
5.6
5.4
1200
1000
800
600
–3 –2 –1 0 1 2 3
Start-of-combustion timing (degree ATDC)
–3 –2 –1 0 1 2 3
Start-of-combustion timing (degree ATDC)
–3 –2 –1 0 1 2 3
Start-of-combustion timing (degree ATDC)
–3 –2 –1 0 1 2 3
Start-of-combustion timing (degree ATDC)
–3 –2 –1 0 1 2 3
Start-of-combustion timing (degree ATDC)
–3 –2 –1 0 1 2 3
Start-of-combustion timing (degree ATDC)
EGR rate (%)
Engine coolant heat rejection (including
EGR cooler heat rejection) (Btu/min)
9600
9400
9200
9000
31
30.5
30
29.5
29
28.5
28
27.5
15.16 HD diesel subsystem interaction at rated power, type A9
analysis with fixed A/F ratio = 22 and peak cylinder temperature
= 2439°F (fixed exhaust restriction flow coefficient, fixed EGR cooler
and CAC size).
Diesel-Xin-15.indd 962 5/5/11 12:07:10 PM
963Diesel engine system specification and subsystem interaction
© Woodhead Publishing Limited, 2011
compensate for that, a smaller turbine area needs to be used to restore the
turbocharger speed and the boost pressure. As a result, the EGR valve has
to be closed more, and as a result the engine delta P and the pumping loss
increase. Figure 15.13 illustrates such an effect.
Turbine effective area (cm
2
)
BSFC (lb/(hp.hr))
Engine delta P (mbar)
Exhaust restriction flow coefficient
Total exhaust restriction (inch Hg)Total exhaust restriction (inch Hg)
Total exhaust restriction (inch Hg)
Total exhaust restriction (inch Hg)
Total exhaust restriction (inch Hg)
Total exhaust restriction (inch Hg)
15
14
13
12
11
10
9
8
7
6
5
4
15
14
13
12
11
10
9
8
7
6
5
4
15
14
13
12
11
10
9
8
7
6
5
4
15
14
13
12
11
10
9
8
7
6
5
4
15
14
13
12
11
10
9
8
7
6
5
4
15
14
13
12
11
10
9
8
7
6
5
4
A/F ratio
Exhaust manifold gas temperature
(static) (°F)
0.2 0.3 0.4 0.5 0.6 0.7 0.8
Lumped EGR circuit flow coefficient
0.2 0.3 0.4 0.5 0.6 0.7 0.8
Lumped EGR circuit flow coefficient
0.2 0.3 0.4 0.5 0.6 0.7 0.8
Lumped EGR circuit flow coefficient
0.2 0.3 0.4 0.5 0.6 0.7 0.8
Lumped EGR circuit flow coefficient
0.2 0.3 0.4 0.5 0.6 0.7 0.8
Lumped EGR circuit flow coefficient
0.2 0.3 0.4 0.5 0.6 0.7 0.8
Lumped EGR circuit flow coefficient
7
6.5
6
5.5
26
24
22
20
18
0.42
0.415
0.41
0.405
0.4
0.395
0.39
0.385
0.24
0.22
0.2
0.18
0.16
1150
1100
1050
1000
1400
1200
1000
800
600
400
200
15.17 HD diesel A/F ratio effect at rated power, type B1 analysis with
EGR rate = 31%.
Diesel-Xin-15.indd 963 5/5/11 12:07:11 PM
964 Diesel engine system design
© Woodhead Publishing Limited, 2011
Turbine effective area (cm
2
)
BSFC (lb/(hp.hr))
Engine delta P (mbar)
Lumped EGR circuit flow coefficient
Overall turbine efficiency
Overall turbine efficiency
Overall turbine efficiency
Overall turbine efficiencyOverall turbine efficiencyOverall turbine efficiency
0.76
0.74
0.72
0.7
0.68
0.66
0.64
0.62
0.6
0.58
0.76
0.74
0.72
0.7
0.68
0.66
0.64
0.62
0.6
0.58
0.76
0.74
0.72
0.7
0.68
0.66
0.64
0.62
0.6
0.58
0.76
0.74
0.72
0.7
0.68
0.66
0.64
0.62
0.6
0.58
0.76
0.74
0.72
0.7
0.68
0.66
0.64
0.62
0.6
0.58
0.76
0.74
0.72
0.7
0.68
0.66
0.64
0.62
0.6
0.58
A/F ratio
Turbine power (kW)
0.018 0.02 0.022 0.024 0.026
Corrected turbine flow rate
0.018 0.02 0.022 0.024 0.026
Corrected turbine flow rate
0.018 0.02 0.022 0.024 0.026
Corrected turbine flow rate
0.018 0.02 0.022 0.024 0.026
Corrected turbine flow rate
0.018 0.02 0.022 0.024 0.026
Corrected turbine flow rate
0.018 0.02 0.022 0.024 0.026
Corrected turbine flow rate
6.6
6.4
6.2
6
5.8
5.6
5.4
25
24
23
22
21
20
19
0.42
0.415
0.41
0.405
0.4
0.395
0.39
0.35
0.3
0.25
0.2
55
50
45
40
35
30
25
1600
1400
1200
1000
800
600
400
15.18 HD diesel A/F ratio effect at rated power, type B2 analysis with
EGR rate = 31%.
Cooling system design has an impact on pumping loss through intake
manifold gas temperature and the ow restriction of EGR cooler or charge air
cooler. Higher cooler effectiveness and lower restriction result in less required
Diesel-Xin-15.indd 964 5/5/11 12:07:11 PM
965Diesel engine system specification and subsystem interaction
© Woodhead Publishing Limited, 2011
BSFC (lb/(hp.hr))
O
2
mass fraction
Turbine effective area (cm
2
)
Peak cylinder temperature (°F)
Overall turbocharger efficiency
Engine delta P (mbar)
2900
2800
2700
2600
2500
2400
2300
2200
25
24
23
22
21
20
19
18
17
16
25
24
23
22
21
20
19
18
17
16
25
24
23
22
21
20
19
18
17
16
25
24
23
22
21
20
19
18
17
16
25
24
23
22
21
20
19
18
17
16
25
24
23
22
21
20
19
18
17
16
A/F ratioA/F ratioA/F ratio
A/F ratio
A/F ratioA/F ratio
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
7.5
7
6.5
6
5.5
0.56
0.54
0.52
0.5
0.48
0.46
0.44
0.415
0.41
0.405
0.4
0.395
0.39
0.195
0.19
0.185
0.18
0.175
0.17
0.165
0.16
1200
1000
800
600
400
15.19 HD diesel air system capability at rated power, type C1 analysis
with IMT = 150°F, exhaust restriction = 9.7 inch Hg, EGR valve fully
open, and turbine wastegate fully closed.
Diesel-Xin-15.indd 965 5/5/11 12:07:12 PM
966 Diesel engine system design
© Woodhead Publishing Limited, 2011
15.20 HD diesel air system capability at rated power, type C2
analysis with IMT = 150°F, exhaust restriction = 9.7 inch Hg, overall
turbocharger efficiency = 53%, and turbine wastegate fully closed.
BSFC (lb/(hp.hr))
Compressor outlet temperature (°F)
Turbine effective area (cm
2
)
Lumped EGR circuit flow coefficient
Engine delta P (mbar)
Engine coolant heat rejection
(including EGR cooler heat
rejection) (Btu/min)
26
25
24
23
22
21
20
19
18
17
26
25
24
23
22
21
20
19
18
17
26
25
24
23
22
21
20
19
18
17
26
25
24
23
22
21
20
19
18
17
26
25
24
23
22
21
20
19
18
17
26
25
24
23
22
21
20
19
18
17
A/F ratioA/F ratioA/F ratio
A/F ratioA/F ratio A/F ratio
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
20 25 30 35
EGR rate (%)
0.35
0.3
0.25
0.2
7.5
7
6.5
6
5.5
380
360
340
320
300
280
260
240
10500
10000
9500
9000
8500
8000
0.42
0.415
0.41
0.405
0.4
0.395
0.39
1600
1400
1200
1000
800
600
400
System design point
Diesel-Xin-15.indd 966 5/5/11 12:07:12 PM
967Diesel engine system specification and subsystem interaction
© Woodhead Publishing Limited, 2011
engine delta P to drive a target air–fuel ratio and EGR rate, especially at peak
torque where the EGR valve is usually fully open. Then, a larger turbine area
can be selected to reduce the pumping loss. There are trade-offs between cooler
BSFC (lb/(hp.hr))
Compressor outlet temperature [°F]
Turbine wastegate opening (mm)Turbine effective area (cm
2
)
Engine delta P (mbar)
Peak cylinder pressure (psi, absolute)
23
22
21
20
19
18
17
23
22
21
20
19
18
17
23
22
21
20
19
18
17
23
22
21
20
19
18
17
23
22
21
20
19
18
17
23
22
21
20
19
18
17
A/F ratioA/F ratio
A/F ratio
A/F ratioA/F ratio
A/F ratio
25 30 35
EGR rate (%)
25 30 35
EGR rate (%)
25 30 35
EGR rate (%)
25 30 35
EGR rate (%)
25 30 35
EGR rate (%)
25 30 35
EGR rate (%)
7.5
7
6.5
6
5.5
5
4.5
10
8
6
4
2
0
360
340
320
300
280
260
240
2200
2100
2000
1900
1800
1700
1600
1500
0.41
0.405
0.4
0.395
0.39
1000
800
600
400
15.21 HD diesel air system capability at rated power, type C3
analysis with IMT = 150°F, exhaust restriction = 9.7 inch Hg, overall
turbocharger efficiency = 53%, and EGR valve fully open.
Diesel-Xin-15.indd 967 5/5/11 12:07:12 PM
968 Diesel engine system design
© Woodhead Publishing Limited, 2011
effectiveness, cooler ow restriction, and packaging size. Figures 15.11–15.12
illustrate the effect of cooler size in engine system design.
Two-stage turbocharging has been adopted for high power-rating engines
with high EGR rate due to the high boost pressure required. A lower pressure
at the low-pressure-stage turbine inlet generally results in an increase in the
high-pressure-stage turbine power and a decrease in the low-pressure-stage
turbine power. An advanced approach to analyzing the turbine area sizing
of the two stages and the interaction between the two stages is to conduct
minimum-BSFC optimization under xed emissions (or their approximation
as a xed air–fuel ratio and EGR rate) at rated power and peak torque. Such
an optimization is illustrated in Fig. 15.22. In the gure, the horizontal
axis represents the high-pressure-stage turbine area, and the vertical axis
represents the low-pressure-stage turbine area. It is observed that the
EGR–turbocharger hardware capability and the range of controllability are
very different at different speed–load modes. A compromise usually needs
to be made to select the best turbocharger sizes for both stages. A similar
dilemma exists regarding using a small turbine or using an intake throttle.
Using a small turbine may help drive EGR at peak torque but causes higher
pumping loss at rated power when the turbine is wastegated or bypassed.
In contrast, using an intake throttle at peak torque may increase EGR rate
slightly (with a penalty of a large reduction in the air–fuel ratio) so that a
larger turbine may be selected for peak torque. Although the BSFC at rated
power becomes lower due to the larger turbine, using intake throttle results
in a BSFC penalty at peak torque. The wider the engine speed range, the
more difcult the trade-off. The best solution is to use a VGT. If a VGT is
not used, a wise compromise needs to be made on the turbine size based on
the vehicle’s frequent operating modes (low engine speed vs. high speed)
and transient acceleration requirements.
To summarize, although the engine hardware selection process is interactive
between subsystems, the following can be used as a general guideline for the
sequence: (1) exhaust restriction; (2) charge air cooler and EGR cooler capacity;
(3) EGR circuit ow restriction; and (4) turbocharger. The above discussions
are for engine systems with a conventional valvetrain (cam). For subsystem
interaction involving VVA, the engine performance can be best analyzed by
using the air system capability chart shown in Fig. 9.12(c) in Chapter 9.
After the air system hardware has been specied for critical modes in the
normal and extreme ambient conditions, a simulation of virtual performance
and emissions calibration in the entire engine speed–load domain needs to
be conducted with proper parameter smoothing over the entire domain (an
example is shown in Fig. 7.8). Transient powertrain simulation also needs to
be carried out to evaluate the hardware’s transient capability and electronic
control algorithms.
A bibliography of other applications of diesel engines is listed for
completeness.
Diesel-Xin-15.indd 968 5/5/11 12:07:12 PM
969Diesel engine system specification and subsystem interaction
© Woodhead Publishing Limited, 2011
15.5 References and bibliography
Asad U and Shaque U A (2001), ‘Dual-fuel system for heavy duty truck engines’,
ASME paper 2001-ICE-423.
X
2
-LP turbine mass multiplier
X
2
-LP turbine mass multiplierX
2
-LP turbine mass multiplier
X
2
-LP turbine mass multiplierX
2
-LP turbine mass multiplier
X
2
-LP turbine mass multiplier
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
1.3
1.2
1.1
1
0.9
0.8
1.3
1.2
1.1
1
0.9
0.8
1.3
1.2
1.1
1
0.9
0.8
1800
1600
1400
1200
1000
800
15
10
5
0
0.28
0.26
0.24
0.22
0.2
0.18
0.16
1200
1000
800
600
400
200
90
80
70
60
50
40
30
20
10
0.7 0.8 0.9 1 1.1 1.2 1.3
X
1
-HP turbine mass multiplier
0.7 0.8 0.9 1 1.1 1.2 1.3
X
1
-HP turbine mass multiplier
0.7 0.8 0.9 1 1.1 1.2 1.3
X
1
-HP turbine mass multiplier
0.7 0.8 0.9 1 1.1
X
1
-HP turbine mass multiplier
0.7 0.8 0.9 1 1.1
X
1
-HP turbine mass multiplier
0.7 0.8 0.9 1 1.1
X
1
-HP turbine mass multiplier
X
3
-HP turbine bypass valve opening (mm)
X
5
-lumped EGR valve opening C
d,EGR
X
5
-lumped EGR valve opening C
d,EGR
X
4
-intake throttle valve opening (degree)
Engine delta P
(mbar)
Rated power, at fixed A/F ratio and
EGR rate, the controllability of HP-stage
turbine bypass valve opening and EGR
valve opening and pumping loss
Engine delta P
(mbar)
Peak torque, at another pair of fixed
A/F and EGR rate, the controllability of
intake throttle valve opening and EGR
valve opening and pumping loss
0.7
0.6
0.5
0.4
0.3
0.2
BSFC
decreases
15.22 Simulation optimization of two-stage turbocharging.
Diesel-Xin-15.indd 969 5/5/11 12:07:13 PM
970 Diesel engine system design
© Woodhead Publishing Limited, 2011
Berard F, Cotta A, Stokes J, Thring R and Wheals J (2000), ‘An integrated powertrain
(IPT) model – stage one’, SAE paper 2000-01-0864.
Boggs D L, Belaire R C, Bartunek B, Durnholz M and Ecker H-J (1997), ‘A small
displacement DI diesel engine concept for high fuel economy vehicles’, SAE paper
972680.
Burtt D J and James I B (2004), ‘Use of system design techniques in the optimization of
integrated powertrains incorporating an IVT’, SAE paper 2004-01-0352.
Chen S K, Mather D and Reitz R (1997), ‘Current and advanced design concepts for high
power-density mid-range truck diesel engines, part II: the development of advanced
design process for combustion system optimization’, SAE paper 972689.
Conley J and Taylor S (2002), ‘Technological evaluation of fuel efciency improvement
concepts to meet future regulatory requirements in the North American market’, SAE
paper 2002-01-2809.
Demirbas A (2008), Biodiesel: A Realistic Fuel Alternative for Diesel Engines, Springer-
Verlag London Limited, London.
Eberhardt J J (1999), ‘Overview of the DOE heavy vehicle technologies R&D program’,
SAE paper 1999-01-2235.
Fussey P M, Goodfellow C L, Oversby K K, Porter B C and Wheals J C (2001), ‘An
integrated powertrain (IPT) model – stage 2: systems integration, supervisory control
and simulation of emissions control technology’, SAE paper 2001-01-0938.
Georgi B, Hunkert S, Liang J and Willmann M (1997), ‘Realizing future trends in diesel
engine development’, SAE paper 972686.
Hikosaka N (1997), ‘A view of the future of automotive diesel engines’, SAE paper
972682.
Hountalas D T (2000), ‘Available strategies for improving the efciency of DI diesel
engines – a theoretical investigation’, SAE paper 2000-01-1176.
Khair M K (1997), ‘Technical and synergistic approaches towards the twenty-rst century
diesel engine’, SAE paper 972687.
May M P, Vertin K, Ren S, Gui X, Myburgh I and Schaberg P (2001), ‘Development
of truck engine technologies for use with Fischer–Tropsch fuels’, SAE paper 2001-
01-3520.
Merrion D F (1994), Diesel Engine Design for the 1990s, the 40th L. Ray Buckendale
Lecture, SAE SP-1011, SAE paper 940130, SAE International, Warrendale, PA.
Page D L and Edgar B L (1998), ‘A systems-level optimization strategy for diesel
engines’, SAE paper 981914.
Pahl G (2008), Biodiesel: Growing a New Economy, 2nd edn, Chelsea Green Publishing,
White River Junction, VT.
Rakopoulos C D, Hountalas D T, Zannis T C and Levendis Y A (2004), ‘Operational
and environmental evaluation of diesel engines burning oxygen-enriched intake air
or oxygen-enriched fuels: a review’, SAE paper 2004-01-2924.
Regueiro J F and Chen S K (1997), ‘Current and advanced design concepts for high
power-density mid-range truck diesel engines, part I: technology review’, SAE paper
972688.
Rickeard D J, Bonetto R and Signer M (1996), ‘European programme on emissions,
fuels and engine technologies (EPEFE) – comparison of light and heavy duty diesel
studies’, SAE paper 961075.
Schindler K-P (1997), ‘Why do we need the diesel?’, SAE paper 972684.
Scott W M (1984), ‘The passenger car diesel engine – present and future’, in Haddad S
D and Watson N (eds), Design and Applications in Diesel Engineering, Ellis Horwood
Limited, Chichester.
Diesel-Xin-15.indd 970 5/5/11 12:07:13 PM
971Diesel engine system specification and subsystem interaction
© Woodhead Publishing Limited, 2011
Silva D F C (2006), ‘DME as alternative diesel fuel: overview’, SAE paper 2006-01-
2916.
Singh G, Graves R L, Storey J M, Partridge W P, Thomas J F, Penetrante B M, Brusasco
R M, Merritt B T, Vogtlin G E, Aardahl C L, Habeger C F and Balmer M L (2000),
‘Emission control research to enable fuel efciency: Department of Energy heavy
vehicle technologies’, SAE paper 2000-01-2198.
Taylor R I (2000), ‘Heavy duty diesel engine fuel economy: lubricant sensitivities’, SAE
paper 2000-01-2056.
Thompson N, Ntziachristos L, Samaras Z, Aakko P, Wass U, Hausberger S and Sams
T (2004), ‘Overview of the European “particulates” project on the characterization
of exhaust particulate emissions from road vehicles: results for heavy duty engines’,
SAE paper 2004-01-1986.
Yang Z (2002), ‘A study of two-stroke engine braking for HD diesel engines’, SAE
paper 2002-01-0487.
15.5.1 References and bibliography on other applications
of diesel engines
Light-duty diesel engines
Andersson J D, Wedekind B G A, Hall D, Stradling R and Wilson G (2001), ‘DETR/
SMMT/CONCAWE particulate research programme: light duty results’, SAE paper
2001-01-3577.
Cooper B, Penny I, Beasley M, Greaney A and Crump J (2006), ‘Advanced diesel
technology to achieve Tier 2 Bin 5 emissions compliance in US light-duty diesel
applications’, SAE paper 2006-01-1145.
Cowland C, Gutmann P and Herzog P L (2004), ‘Passenger vehicle diesel engines for
the US’, SAE paper 2004-01-1452.
Hublin M, Gadd P G, Hall D E and Schindler K P (1996), ‘European programmes on
emissions, fuels and engine technologies (EPEFE) – light duty diesel study’, SAE
paper 961073.
Krieger R B, Siewert R M, Pinson J A, Gallopoulos N E, Hilden D L, Monroe D R,
Rask R B and Solomon A S P (1997), ‘Diesel engines: one option to power future
personal transportation vehicles’, SAE paper 972683.
Majewski W A and Khair M K (2006), Diesel Emissions and Their Control, SAE
International, Warrendale, PA.
McDonald J (2004), ‘Progress in the development of Tier 2 light-duty diesel vehicles’,
SAE paper 2004-01-1791.
Mital R, Li J, Huang S C, Stroia B J, Yu R C, Anderson J A and Howden K (2003), ‘Diesel
exhaust emissions control for light duty vehicles’, SAE paper 2003-01-0041.
Morey C J and Mark J (2000), ‘Diesel passenger vehicles – can they meet air quality
needs and climate change goals?’, SAE paper 2000-01-1599.
Ntziachristos L, Mamakos A, Samaras Z, Mathis U, Mohr M, Thompson N, Stradling
R, Forti L and de Serves C (2004), ‘Overview of the European “particulates” project
on the characterization of exhaust particulate emissions from road vehicles: results
for light-duty vehicles’, SAE paper 2004-01-1985.
Ntziachristos L, Mamakos A, Samaras Z, Rexeis M and Hausberger S (2006), ‘Diesel
particle exhaust emissions from light duty vehicles and heavy duty engines’, SAE
paper 2006-01-0866.
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