T-501 Bernd Friedrich
High Efficient Diesel-Electric
Propulsion
Disclaimer
All data provided on the following slides is for information
purposes only, explicitly non-binding and subject to changes
without further notice.
2
Agenda
1
Today´s Diesel-electric propulsion systems & constraints
2
New system approach for a high efficient DE propulsion system
3
Benefits & potentials
4
Measures to improve a Diesel engine´s dynamic
5
Examples
6
Summary
3
Today´s Diesel-electric propulsion system
Some benefits
• High flexible and redundant multi-engine plant
• Low fuel oil consumption at part load due to a
Gensets
better loading of (running) engines
• Improved manoeuvrability with precise control of
Switchboards
propulsors (i.e. azimuth thrusters, pods)
• High propeller efficiency. Usually FP propellers
are applied, always operating at design pitch
• The FPP can be operated in an extended range compared to DM propulsion - due to the speedtorque-characteristic of the E-motor
• High torque performance also at low speeds (i.e.
Variable speed drives:
- Supply Trafo *)
- Frequency converter
- E-Propulsion motor
icy conditions). “Easy” over-torque / constant
power capability (i.e. heavy weather) via FWP
adjustment of the drives
• Flexibility in propulsion plant arrangement
• Increased payload as DE engine rooms usually
take up less space ( shorter)
• Lower noise and vibrations, especially when
using i.e. pods or gearless solutions
Gearbox *)
Propellers /
Propulsors
*) In some applications not needed:
Dependent on the type of converter
and speed of E-motor
4
Diesel-electric propulsion plants
Typical example of an offshore application: PSV
Source: Ulstein
2 x 8L21/31 @ 900 rpm (= 2 x 1672 kWel)
2 x 9L21/31 @ 900 rpm (= 2 x 1881 kWel)
690 V AC MSB, 60 Hz
2 x Azimuth thruster
(= 2 x 2000 kW)
2 x Frequency converter: PWM-type, 12 p
2 x Supply transformer
2 x Bow thruster
(= 2 x 880 kW)
2 x Autotransformer starter
5
Losses in a DE propulsion plant
From fuel to shaft power (at the E-motor)
 72%
 53%
Full
load
Low
load
 4%
 3%
 0,2%
 1%
 1,5%
 4%
Total losses 
63%
 0,2%
 1,5%
 2%
 5%
Total losses 
85%
How can we operate the Diesel engine more efficiently ?
6
Agenda
1
Today´s Diesel-electric propulsion systems & constraints
2
New system approach for a high efficient DE propulsion system
3
Benefits & potentials
4
Measures to improve a Diesel engine´s dynamic
5
Examples
6
Summary
7
Engine operation map
SFOC map: 27/38 engine
Engine Output
100 %
Variable speed operation:
184 g/kWh
Constant speed operation:
187 g/kWh
50 %
10 %
60 %
Engine Speed
83 %
100 %
8
A “new” system concept by E-suppliers
Good old DC is coming back !
The electric system is an enabler for the Diesel engine
Classical DE propulsion system
“New” electric system concept
- “Existing” components are arranged in a new way.
- In total comparable number of electric devices compared with a classical DE system.
9
Agenda
1
Today´s Diesel-electric propulsion systems & constraints
2
New system approach for a high efficient DE propulsion system
3
Benefits & potentials
4
Measures to improve a Diesel engine´s dynamic
5
Examples
6
Summary
10
EPROX = Electric Propulsion Excellence
1.) DC technology facilitates potentials for fuel saving
System features:
A DC distribution removes the classical AC main
switchboard
• Alternators are connected via rectifiers
• Propulsion motors (IM) are connected and
speed controlled via inverters
The
Diesel
engines
can
independently on variable speeds
operate
No synchronisation of alternators needed
PMS gives individual speed set points to the
gensets acc. to the current power demand,
operating each engine on its optimal sfoc
point
Example: Variable speed gensets 4 x 6L32/44CR
4 x 3600 kWm: Total system load is 8000 kW
with 3 engines running
#1
#3
89%@750rpm
44%@630rpm
#2
89%@750rpm
#4 = off
12
EPROX = Electric Propulsion Excellence
1.) DC technology facilitates potentials for fuel saving
System features:
A DC distribution removes the classical AC main
switchboard
• Alternators are connected via rectifiers
• Propulsion motors (IM) are connected and
speed controlled via inverters
The
Diesel
engines
can
independently on variable speeds
operate
No synchronisation of alternators needed
PMS gives individual speed set points to the
gensets acc. to the current power demand,
operating each engine on its optimal sfoc
point
Possibility to integrate
devices (i.e. batteries)
energy
storage
Remarks:
- System available up to 20 MW installed genset
power
- DC on board is not „common“
EPROX = Electric Propulsion Excellence
2.) DC technology boosts the dynamic plant performance
System features:
Energy storage sources (i.e. batteries) can be
integrated into the system
•
Batteries are connected to the DC grid via
DC/DC converters
Energy storage sources can be used to reduce
transient loads on the engines
Faster dynamic system response, improving
the load acceptance for our engines,
i.e. Dual Fuel engine in DP mode
Load peaks are shaved and buffered by the
batteries
Sfoc saving via batteries
Batteries enable a high loading of the Diesel engines
Battery
charge
Battery
discharge
Battery
discharge
Battery
charge
System load
Load 1
Load 2
Genset 3
Genset 3 *)
Genset 2 *)
Genset 2
Genset 2
Genset 2
Genset 1 *)
Genset 1
Genset 1
Genset 1
*) Genset operating at 85% load  Minimum SFOC
15
Agenda
1
Today´s Diesel-electric propulsion systems & constraints
2
New system approach for a high efficient DE propulsion system
3
Benefits & potentials
4
Measures to improve a Diesel engine´s dynamic
5
Examples
6
Summary
16
Apart from batteries – How can we
improve the engine´s dynamic ?
Excursion: Common rail injection system
1600
Conventional
injection system:
1200
cam controlled
Inj. pressure
Injection2000
pressure  Pressure generation
800
1350 bar
700 bar
n = High rpm
rpm dependent
n = Low rpm
400
0
Inj. pressure
Common Rail
injection system
camshaft angle
1600 bar
rpm independent
flexible set point
rpm independent and flexible:
injection timing & multiple injection
500 bar
camshaft angle
Measures to improve a Diesel´s dynamic
Jet Assist and Boost Injection
 For load application an engine has to increase:
• Fuel
• Air
 If an engine detects a sudden load increase it
changes:
• Injection timing to 4°CA (2°CA) earlier
• Increase rail pressure about 200 bar
 This changes lead to a higher engine torque
A Start-air bottle
(30 bar)
C Compressor wheel
1 Solenoid valve
3 Pressure reduce orifice
4 Ring duct jet air
5 Air insert
6 Bores
7 Compressor casing
6
7
5
C
4
1
3
A
18
Transient Behavior
Jet Assist and Boost Injection (20V32/44CR)
Load-Step
rpm 725
45
720
Engine speed
50
40
30
25
%
Base engine
710
with Jet Assist
705
700
60
with Boost Inj.
20
15
Opacity
Load [%]
35
715
10
40
with Jet & Boost
20
5
0
0
-5
0
5
10
Time [sec]
15
0
5
Time [sec]
10
s
With DC grid technology, jet assist & boost injection an E-proplusion system is fit for high performant
applications
Agenda
1
Today´s Diesel-electric propulsion systems & constraints
2
New system approach for a high efficient DE propulsion system
3
Benefits & potentials
4
Measures to improve a Diesel engine´s dynamic
5
Examples
6
Summary
20
Example - PSV
Engine with conventional injection system (L27/38)
The average SFOC saving is in a significant range
Vessel data:
Length o.a.:
Dead weight:
Max. speed:
Eco. speed:
94 m
4500 t
15 kts
10 kts
Main gensets:
Azimuth thrusters:
Bow thrusters:
 SFOC [g/kWh]
 SFOC saving
[g/kWh]
1
580
185
13
2
600 / 500
184
9
2416
2
600 / 600
183
4
Engines
running
2640
670
1848
1480
1920
h/year
Standby Offshore
Dynamic Positioning
Transit Eco 10 kts
Transit Full 15 kts
Engine speed [rpm]
Power [kW]
Operational profile
4 x 6L27/38 , 4 x 2190 kW
2 x 3600 kW , FPP
2 x 800 kW , FPP
96
7560
4
660 / 640 / 640 / 640
182
4
In Port
2136
150
1
500
212
46
Out of Service
120
0
0
-
-
-
Example - AHTS
Engine with common rail injection system (L32/44CR)
The flexibility of the CR system supports variable speed
operation
Vessel data:
Length o.a.:
Dead weight:
Max. speed:
Cruising speed:
76,5 m
3000 t
16 kts
12 kts
Main generator engines:
Propellers:
Bow thrusters:
Stern thrusters:
4 x 6L32/44CR : 4 x 3600 kW @ 450 …750 rpm
2 x 4000 kW, FPP
2 x 1200 kW, FPP
2 x 850 kW, FPP
Agenda
1
Today´s Diesel-electric propulsion systems & constraints
2
New system approach for a high efficient DE propulsion system
3
Benefits & potentials
4
Measures to improve a Diesel engine´s dynamic
5
Examples
6
Summary
23
Summary
1.) „New“ energy-saving solutions have be lauchend on the market for DE propulsion.
DC technology (DC breakers) and AFE converters (for variable input frequency) are the key components.
- ABB: DC Onboard Grid
- Siemens: BlueDrive PlusC
- GE : VF - AFE (75...100% rpm)
2.) For an engine supplier the electric plant is an enbabler to facilitate a saving potential in sfoc by operating
the engines on variable speed.
3.) Engergy storage devices give an additional degree of freedom in DE plant design, especially when it
comes to fast load applications on DF engines.
4.) There a further measures to improve a Diesel engine´s dynamic: Jet Assist and Boost Injection
5.) Calculations show savings in a rage of 3 – 8 g/kWh (depending of op. profile and engine injection system)
Bernd Friedrich
phone: +49-821-322-1627
bernd.friedrich.a@man.eu