Alternative Propulsion Systems and Energy CarriersAustrian, European and global R&D- and demonstration projects,
research institutions and funding programs
Vienna, 16.10.2009 in cooperation with
Emission Behavior and Efficiency of SI Engines Operated with Biogas
Heiko Pflaum, Bernhard Geringer, Peter Hofmann
2Rethinking Propulsion.
1. Introduction
2. Test engine
3. Comparison of Biogas with Eurosuper 95 and CNG
• Part Load
• Full Load
4. Comparison of different Biogas qualities (CO2-content)
5. Conclusions
Content
1. Introduction
2. Test engine
3. Comparison of Biogas with Eurosuper 95 and CNG
• Part Load
• Full Load
4. Comparison of different Biogas qualities (CO2-content)
5. Conclusions
3Rethinking Propulsion.
Almost Closed CO2-Cycle:further reductionof CO2-emissions
Motivation
EU Legislation:CO2-reduction
emission standardsindependence of fossil fuels
High Knock Resistance:advantage at fullload conditions
Lower C/H-Ratio:reduction of CO2-emissions
4Rethinking Propulsion.
CO2-content:Reduction of gas-quality
due to higher CO2-content
Motivation
Hydrogen-content:Increased gas-quality
due to higher H2-content
Biogas processing:Engine potential of
different processing steps
real Biogas,not simulated
5Rethinking Propulsion.
Composition of raw Biogas
<3mg/m3CFC
0 – 1Vol%Ammoniac
0 – 2Vol%Sulfide
0 – 2Vol%Oxygen
0 – 1Vol%Hydrogen
0 – 20Vol%Nitrogen
14 – 55Vol%Carbon dioxide
40 – 80Vol%Methane
GehaltEinheitcomponent
Composition for recovery from fermentative processes
Methane enrichment by separation of CO2Natural gas quality: CH4 ≥ 96% (AUT)
Separation during Biogas processing
Source: Mayer, T., Hofbauer, H., Vienna University of Technology 2008
6Rethinking Propulsion.
1. Introduction
2. Test engine
3. Comparison of Biogas with Eurosuper 95 and CNG
• Part Load
• Full Load
4. Comparison of different Biogas qualities (CO2-content)
5. Conclusions
Content
7Rethinking Propulsion.
Test engine and experimentation
Intake-manifold fuel injectionmixture preparation
12,5 : 1Compression ratio
135 / 4200Nm / rpmmax. torque / rpm
71 / 6200kW / rpmeffective power / rpm
79 x 81,5mmbore x stroke
1598cm3displacement
4 cylinder /in-line, 4 valves per cylindercylinder / alignment
high compression ratiofor gas operation
Separated injection valvesfor gas- and liquid fuel operation
All experiments carried out with stoichiometric air ratio (except assembly protection with Eurosuper 95)
All measurements of exhaust emissions in raw exhaust before oxidation catalyst
1,6 l engine,natural aspirated
8Rethinking Propulsion.
1. Introduction
2. Test engine
3. Comparison of Biogas with Eurosuper 95 and CNG
• Part Load
• Full Load
4. Comparison of different Biogas qualities (CO2-content)
5. Conclusions
Content
9Rethinking Propulsion.
Results for Eurosuper 95, CNG and Biogas,load point 2000 rpm – 2 bar BMEP
0
20
40
60
80
100
120
CO2Tank toWheel
CO2Well toWheel
HC CO NOx
spez
. raw
em
issi
ons
refe
renc
ed to
Euro
supe
r 95
[%]
CNGBiogas 97
Eurosuper 95 = 100%
engineoperation
path oflife*
CNG: Rest CxHyBiogas: Rest CO2
*Quelle: Edwards, R. et al, November 2008
-60% to -70%
band width
10Rethinking Propulsion.
Results for Eurosuper 95, CNG and Biogas,load point 2000 rpm – 2 bar BMEP
-30 -20 -10 -0 10 20 30 40 50 60 70 80 90Kurbelwinkel [Grad]
Bren
nrau
mte
mpe
ratu
r [K]
0
300
600
900
1200
1500
1800
2100
2400
2700
3000
Super 95Biogas 97
*Quelle: Edwards, R. et al, November 2008
Higher hydrogen content in gaseous fuelsmore H2O as combustion productreduced combustion temperatures
crank angle [degree]
Com
bust
ion
tem
pera
ture
[K]
11Rethinking Propulsion.
1. Introduction
2. Test engine
3. Comparison of Biogas with Eurosuper 95 and CNG
• Part Load
• Full Load
4. Comparison of different Biogas qualities (CO2-content)
5. Conclusions
Content
12Rethinking Propulsion.
6
7
8
9
10
11
12
1000 2000 3000 4000 5000 6000engine speed [rpm]
BM
EP [b
ar]
Super 95CNGBiogas 97
Results for Eurosuper 95, CNG and Biogasat full load conditions
Late combustion for Eurosuper 95High exhaust gas temperaturescatalyst overheating protection
up to -10%
13Rethinking Propulsion.
0
100
200
300
400
500
600
700
800
900
1000
1000 2000 3000 4000 5000 6000engine speed [rpm]
Ener
gy c
onte
nt in
com
bust
ion
cham
ber B
renn
raum
[kJ/
h]fo
r sto
ichi
omet
ric c
ombu
stio
n Super 95CNGBiogas 97
Results for Eurosuper 95, CNG and Biogasat full load conditions
Reduced mixture heat value with gas operation:
reduction of full load torque of up to 10%
-20%
14Rethinking Propulsion.
25
27
29
31
33
35
37
1000 2000 3000 4000 5000 6000engine speed [rpm]
effic
ienc
y [%
]
Super 95CNGBiogas 97
catalyst overheating protectionfor Eurosuper 95
+2,7%
Results for Eurosuper 95, CNG and Biogasat full load conditions
15Rethinking Propulsion.
0
5
10
15
20
25
30
35
1000 2000 3000 4000 5000 6000engine speed [rpm]
50%
mas
s fr
actio
n bu
rned
[°C
AaT
DC
]
Super 95CNGBiogas 97
Late combustion necessary toprevent knocking with ROZ 95
Results for Eurosuper 95, CNG and Biogasat full load conditions
16Rethinking Propulsion.
32,9
4,6
7,9
35,7
7,9
0,9
35,6
7,7
0,9
0
10
20
30
40
50
60
70
Super CNG Biogas
efficiency loss realcombustion
efficiency loss realcharge
efficiency losscombustion position
efficiency lossunburned
efficiency loss wallheat
efficiency loss gasexchange
efficiency lossfriction
efficiency(measured)
Thermal efficiency = 63,5%
Higher efficiencywith gaseous fuels
7% advantage for gas as result ofoptimum combustion timing
advantage of highoctane number
Late combustion with EurosuperResults in low gastemperatures (pmax drops)
reduction of wall heat losses
Results for Eurosuper 95, CNG and Biogasat 2000 rpm, full load
17Rethinking Propulsion.
1. Introduction
2. Test engine
3. Comparison of Biogas with Eurosuper 95 and CNG
• Part Load
• Full Load
4. Comparison of different Biogas qualities (CO2-content)
5. Conclusions
Content
18Rethinking Propulsion.
Results for different Biogas qualities (CO2-content), load point 2000 rpm – 2 bar BMEP
0
20
40
60
80
100
120
140
Efficiency CO2 HC CO NOxspez
. raw
em
issi
ons
and
effic
ienc
y re
fere
nced
toB
ioga
s (9
7% M
etha
ne) [
%]
Biogas 84% MethaneBiogas 80% Methane
Biogas 97% Methane = 100%
CO2 contained in fuel isemitted in the exhaust gas
Reduction of NOx-emissions due to higherCO2 content reduction of Temperature
19Rethinking Propulsion.
1. Introduction
2. Test engine
3. Comparison of Biogas with Eurosuper 95 and CNG
• Part Load
• Full Load
4. Comparison of different Biogas qualities (CO2-content)
5. Conclusions
Content
20Rethinking Propulsion.
Biogas proofed equal potential as CNG in the engine operationlife cycle Biogas reduces CO2 emissions by 60% to 70% compared to Eurosuperincreased efficiency at full load conditions as result of high knock resistance of Biogasdecreased full load torque for naturally aspirated engine, but same for turbocharged engineSame or even better emission level for lower Biogas qualities (CO2-content)
Requires changed logistic
Conclusions
21Rethinking Propulsion.
Contact
Heiko PflaumInstitute for ICE and Automotive Engineering
Address: Getreidemarkt 91060 Wien
Tel: +43-(0)1-58801 30015Fax: +43-(0)1-58801 31599web: www.ivk.tuwien.ac.atEmail: [email protected]
22Rethinking Propulsion.
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