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TECHNICAL UNIVERSITY OF RADOM
Technical University of Radom, Poland
Sławomir LUFT
Dual-Fuel Compression
Ignition Engine Fuelled
with Methanol or LPG
Ecology and Safety as a Driving Force
in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
Fig. 1. Scheme of fuel system of
dual-fuel C.I. engine operating
on LPG
Fig. 2. Scheme of fuel system of
dual-fuel C.I. engine operating
on methanol
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
ge* 8
[J/Ws] 7
n=1800 rpm
ge* 8
[J/Ws] 7
DF
DF d2 + LPG
6
n=1800 rpm
DF
DF d2 + M
6
5
5
4
4
3
3
2
2
0
10
20
30
40
50
60
0
10
20
30
T [Nm]
40
50
60
T [Nm]
Fig. 3. Comparison of load characteristics of specific energy consumption
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
T 60
[Nm]
T 60
[Nm]
55
55
50
50
7
45
DF
DF d2 + LPG
ge*
[J/Ws]
45
7
DF
DF d2 + M
6
40
6
40
5
35
5
35
4
30
1200
ge*
[J/Ws]
1400
1600
1800
2000
3
2200
4
30
1200
1400
1600
1800
n [rpm]
2000
3
2200
n [rpm]
Fig. 4. Comparison of maximal torque values M for the standard engine
operating on diesel fuel (αi = 30o BTDC) and for dual fuelled engine operating
on LPG (αi = 20o BTDC) and methanol (αi = 27o BTDC)
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
CO 3
[%] 2.5
CO 3
[%] 2.5
n=1800 rpm
DF
2
DF
2
DF d2 + LPG
1.5
n=1800 rpm
DF d2 + M
1.5
1
1
0.5
0.5
0
0
0
10
20
30
40
50
60
0
10
20
30
40
T [Nm]
50
60
T [Nm]
Fig. 5. Comparison of CO emissions during full-load tests for standard engine
operating on diesel fuel (αi = 30o BTDC) and for dual-fuel engine operating on
LPG (αi = 20o BTDC) and methanol (αi = 27o BTDC) as main fuels
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
NOx 2500
[ppm] 2000
NOx 2500
[ppm] 2000
n=1800 rpm
DF
DF d2 + LPG
DF d2 + M
1500
1500
1000
1000
500
500
0
0
0
10
20
n=1800 rpm
DF
30
40
50
60
0
10
20
30
T [Nm]
40
50
60
T [Nm]
Fig. 6. Comparison of NOx emissions during full-load tests for standard engine
operating on diesel fuel (αi = 30o BTDC) and for dual-fuel engine operating on
LPG (αi = 20o BTDC) and methanol (αi = 27o BTDC) as main fuels
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
HC 400
[ppm]
n=1800 rpm
HC 400
[ppm]
DF
300
300
DF d2 + LPG
200
200
100
100
0
0
0
10
20
30
40
50
n=1800 rpm
60
DF
DF d2 + M
0
10
20
30
T [Nm]
40
50
60
T [Nm]
Fig. 7. Comparison of HC emissions during full-load tests for standard engine
operating on diesel fuel (αi = 30o BTDC) and for dual-fuel engine operating on
LPG (αi = 20o BTDC) and methanol (αi = 27o BTDC) as main fuels
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
S 100
[%] 80
S 100
[%] 80
n=1800 rpm
n=1800 rpm
DF
60
DF
60
DF d2 + LPG
40
40
20
20
0
0
0
10
20
30
40
50
60
DF d2 + M
0
10
20
30
40
T [Nm]
50
60
T [Nm]
Fig. 8. Comparison of smoke emissions during full-load tests for standard
engine operating on standard diesel fuel (αi = 30o BTDC) and for dual-fuel
engine operating on LPG (αi = 20o BTDC) and methanol (αi = 27o BTDC) as
main fuels
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
d [deg of CA]
20
n=1800 rpm
18
16
14
DF
12
DF d2 + LPG
10
DF d2 + M
8
0
10
20
30
40
50
60
T [Nm]
Fig. 9. Comparison of self-ignition delay τd changes versus load for the engine
operating on diesel fuel and dual fuelled with LPG and methanol (pilot diesel
fuel injection timing in all cases αi = 30o BTDC)
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
(dp/dav [MPa/deg of CA]
0.6
n=1800 rpm
DF
0.5
DF d2 + LPG
0.4
DF d2 + M
0.3
0.2
0.1
0
10
20
30
40
50
60
T [Nm]
Fig. 10. Comparison of mean rate of pressure rise (dp/dα)av changes versus load
for the engine operating on diesel fuel and dual fuelled with LPG and methanol
(pilot diesel fuel injection timing in all cases αi = 30o BTDC)
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
Pmax 10
[MPa] 9
n=1800 rpm
8
DF
7
DF d2 + LPG
6
DF d2 + M
5
0
10
20
30
40
50
60
T [Nm]
Fig. 11. Comparison of maximal pressure Pmax changes versus load for the
engine operating on diesel fuel and dual fuelled with LPG and methanol (pilot
diesel fuel injection timing in all cases αi = 30o BTDC)
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
p
[MPa]
p
[MPa]
LPG+DF
αi=30 deg of CA BTDC
T=25Nm
p
[MPa]
LPG+DF
αi=30 deg of CA BTDC
T =30Nm
deg of CA
deg of CA
LPG+DF
αi=30 deg of CA BTDC
T =35Nm
deg of CA
p
[MPa]
0,7MPa
LPG+DF
αi=30 deg of CA BTDC
T =40Nm
Fig. 12. Indicator diagrams of single combustion runs for dual fuelled engine
with standard injection timing for diesel fuel pilot dose αi = 30o BTDC
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
p
[MPa]
p
[MPa]
p
[MPa]
LPG+DF
αi=20 deg of CA BTDC
T =35Nm
LPG+DF
αi=20 deg of CA BTDC
T =40Nm
LPG+DF
αi=20 deg of CA BTDC
T =45Nm
deg of CA
deg of CA
deg of CA
p
[MPa]
p
[MPa]
LPG+DF
αi=20 deg of CA BTDC
T =50Nm
LPG+DF
αi=20 deg of CA BTDC
T =55Nm
deg of CA
deg of CA
Fig. 13. Indicator diagrams of single combustion runs for dual fuelled engine
with retarded injection timing for diesel fuel pilot dose αi = 20o of BTDC
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
i = 30 deg of CA BTDC
DF

DF d2 + LPG i = 30 deg of CA BTDC
DF d2 + LPG i = 20 deg of CA BTDC
Pmax 10
[MPa]
0.4
8
0.3
6
0.2
4
0.1
2
i = 30 deg of CA BTDC
DF
(p/)av
MPa
deg of CA
DF d2 + LPG i = 30 deg of CA BTDC
DF d2 + LPG i = 20 deg of CA BTDC
0
0
10
20
30
40
50
60
0
10
20
30
40
T [Nm]
50
60
T [Nm]
Fig 14. Dependence of maximal pressure Pmax and mean rate of pressure rise (dp/dα)av
versus load for standard fuelled engine with standard injection timing αi = 30o BTDC
and for dual fuelled engine with standard injection timing for diesel fuel pilot dose
αi = 30o BTDC and for dual fuelled engine with retarded injection timing
for diesel fuel pilot dose αi = 20o BTDC (engine speed n = 1800 rpm)
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
CONCLUSIONS REGARDING ENGINE
PERFORMANCE
The dual-fuel C.I. engine, for both main fuels discussed in this paper, can
achieve torque values comparable with standard fuelled engine, or even higher,
showing at the same time higher overall efficiency in the range of maximal
loads. This latest feature results from increase of thermal efficiency of dual-fuel
engine cycle.
Decrease of dual-fuel engine overall efficiency in the range of partial loads
results from incomplete combustion of the mixture air-main fuel vapour. This is
confirmed by higher CO and HC emissions in this load range. It should be
stressed here that at partial loads of dual-fuel engine the mixture air-main fuel is
very lean. According to the author, this mixture cannot ignite out of the burning
diesel fuel stream. This effect is favoured by adverse combustion chamber
design, especially between the piston head and flat part of cylinder head behind
toroidal part of combustion chamber located in the piston.
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
CONCLUSIONS REGARDING EXHAUST
EMISSIONS
Decrease of CO emission observed at maximal loads of dual-fuel engine results
from advantageous physico-chemical properties of gaseous fuels from the point of
view their combustion at values of coefficient of excess air that are characteristic
for these conditions. The reasons of CO emission increase at partial loads were
partly given in the conclusion 5.1.
According to the author, decrease of NOx emission (especially at partial loads)
from dual-fuel engine results from the discussed above – in the conclusion 5.1 –
incomplete combustion of the air - main fuel mixture. It leads to temperature
decrease in the combustion chamber in comparison with values appearing in
standard fuelled engine and in consequence – to lower NOx emission.
Increase of HC emission in the range of partial loads results from incomplete
combustion of the air-main fuel mixture in this range and while at loads close to
maximal it may results from incomplete combustion of diesel fuel dose in the
more and more reach air - main fuel mixture.
Decrease of smoke emission for dual-fuel engine is distinctive for combustion of
gaseous fuels and alcohol vapour.
Ecology and Safety as a Driving Force in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008
TECHNICAL UNIVERSITY OF RADOM
Thank you for attention
Ecology and Safety as a Driving Force
in the Development of Vehicles
IP Radom, 02 March – 15 March, 2008