BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Aki Tilli
Ossi Kaario
Martti Larmi
BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Introduction
- Objective: Evaluate renewable diesel compatibilities with
EVE research engine
- Literature study: renewable diesel fuels
- Trad. biodiesel (FAME), HVO (NExBTL), Fischer-Tropsch (BTL), ref: EN 590
- Production, environmental impact, properties
- Simulation model: EVE fuel injection system
- software: GT-FUEL
- Simulations:
- Comparison with reference measurements
- Physical behavior of the biofuels in the fuel injection system
=> boundary conditions for CFD calculations
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
FAME = fatty acid methyl esters
- Competition with food industry; LCA: no CO2 reduction!
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
FAME = fatty acid methyl esters
- Non-toxic; biodegradable; HC, CO, particle emissions reduce
- Thermodynamics: ~ trad. diesel
- Higher density, viscosity, compressibility
=> faster p- pulsations, higher max. pressures, earlier injection
(Yamane et al., 2001)
- Chemical properties problematic
=> engine oil deterioration, corrosion, rubber part deterioration,
storage problems
- High NOx emissions, cold smoking, carbon build-up, cold
operation...
- => max. 5 % blends recommended
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
HVO = Hydrotreated vegetable oil
- From oils and fats:
Competition with food
industry
- Palm oil: deforestration
of rain forests?
Picture:
Neste Oil
- Isoparaffinic
hydrocarbons => nontoxic, no aromatics, no
sulphur
- LCA: CO reduction
considerable
2
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
HVO = Hydrotreated vegetable oil
- High quality: high cetane number, boiling range, adjustable
cold operation properties (process T and p)
- Thermodynamically ~ fossil diesel
- Low density, lubricity
- Emission measurements (VTT, Scania, truck engine
optimized for traditional diesel):
Regulated emissions
Other emissions
• NOx - 0 ... - 20 %
• Aldehydes
- 40 ... - 45 %
• Particles
• Benzene
- 40 ... - 45 %
- 17 ... - 30 %
• CO
- 45 ... - 55 %
• PAH
decrease
• HC
- 45 ... -55 %
• Mutagens
decrease
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Fischer-Tropsch-diesel
- Biomass to liquids BTL, (and GTL, CTL)
- BTL: Biomass gasification => CO ja H (Syngas) => gas
cleaning => FT-synthesis => isoparaffinic hydrocarbons
2
- End product properties adjustable (process p, T)
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Fischer-Tropsch-diesel
- High quality (~ same end-product as HVO, same
properties!)
- Production costs high
- Technology still under development
- BTL: Small volumes, stranded feedstocks, expensive technology
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Fuel comparison and properties
FAME
HVO
BTL
Process
route
Transesterification
Hydrotreatment
Gasification,
FT
Feed
Product
Vegetable oils
Oils, fats
Biomass
Product
(type)
Fatty acid methyl
esters
Isomerized
paraffinic
hydrocarbons
Isomerized
paraffinic
hydrocarbons
Product
quality
Consistency and
stability issues
High
High
CO2
emissions
(LCA)
1.6-2.3 kg CO2/kg
oil equivalent
0.5-1.5 kg
CO2/kg oil
equivalent
0.3-1.5 kg
CO2/kg oil
equivalent
Note: Fossil diesel fuel value reported as 3.8 kg CO2 / kg oil
equivalent (Bown D. 2007)
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- Compressibility: only small
differences => ”only”
injection and spray
optimation challenge
- Cold operation: in research
engine not an issue
- Vapour pressure: very
similar to trad. diesel
- => Density and Viscosity
most important!
BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Fuel comparison and properties
NExBTL
GTL FT
FAME
(RME)
Diesel
Typical
Typical
fuel
EN 590
Density at +15°C (kg/m3)
780 - 785
770- 785
885
835
820-845
Viscosity at +40°C(mm2/s)
3.0 - 3.5
3.2- 4.5
4.5
3.5
2.0-4.5
Cetane number
98 - 99
73 - 81
51
53
>51
10 % distillation (°C)
260- 270
260
340
200
90 % distillation (°C)
295 – 300
325 - 330
355
350
Cloud point (°C)
- 15
0 ... +3
0 ... - 5
-5
Heating value (MJ/kg)
44
43
38
43
Heating value (MJ/l)
34,5
33,8
34
36
Polyaromatics (wt-%)
0
0
0
4
Oxygen content (wt-%)
0
0
11
0
Sulfur content (mg/kg)
< 10
< 10
< 10
< 10
Values: Neste Oil
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Typical
diesel
<11
<50
BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
(Polynomial form)
GTI (Improved power form)
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Simulations: comparison with measurements
Rail pressure (bar)
SOI (deg)
Injection duration (ms)
Injection duration, CA (deg)
EOI (deg)
Injected mass (g)
Simulation: injected mass (g)
simulated inj. mass/real inj. mass
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1400 bar
357.5
5.5
29.7
387.2
1.4778
1.40379
94.99 %
1300 bar
352.6
1.8
9.72
362.32
0.4111
0.441385
107.37 %
1200 bar
350.5
4.25
22.95
373.45
1.0185
0.977956
96.02 %
1100 bar
351.5
3.25
17.55
369.05
0.7037
0.721532
102.53 %
BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Simulated mass flow rates with different biofuels
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Simulated pressures in fuel gallery
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Simulated pressure difference between the fuel
gallery and the volume behind the needle
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Conclusions
- Physical property differences cause only slight deviation
from traditional diesel behavior in the fuel injection system
=> no EVE modifications needed
- Chemical properties may cause problems, if FAME is used
- Lubricity of HVO and FT –fuels must be corrected with
additives (as usual) ...or FAME?
- Next step: fuel spray and combustion optimization, modern
combustion techniques: ReFuel
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BIOFUELS IN THE FUEL INJECTION SYSTEM OF A
SINGLE-CYLINDER MEDIUM-SPEED DIESEL ENGINE
Thank you for your attention!
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