Effects of Ethanol and ETBE Blending in Gasoline on Evaporative

Effects of Ethanol and ETBE Blending in Gasoline on Evaporative
Effects of Ethanol or ETBE Blending
in Gasoline on Evaporative Emissions
Haruya Tanaka
Advanced Technology and Research Institute (ATRI)
Japan Petroleum Energy Center (JPEC)
Japan Petroleum Energy Center
Contents
1. Introduction
2. Test vehicles & Fuels
3. Refueling Loss emission results
• Test method
• Comparison of vehicle type
• Effects of Ethanol / ETBE Blending
4. Running Loss emission results
• Test method
• Comparison of vehicle type, PFI and DISI
• Effects of Ethanol / ETBE Blending
5. Summary & Conclusion
1
Japan Petroleum Energy Center
Introduction
Biomass-derived ethanol is regarded as a carbon neutral fuel
photosynthesis
conversion
combustion
atmospheric
CO2
CH3CH2OH
Ethanol
Biomass Fuel
(Ethanol)
+
CH2=C(CH3)2
iso-Butene
CO2
emission
CH3CH2OC(CH3)3
ETBE (Ethyl tert-Butyl Ether)
In Japan, bio-ethanol or ETBE (Ethyl tert-Butyl Ether) which is synthesized
from bio-ethanol and isobutene, has been promoted as automotive fuel,
and its practical use is under discussion.
Concerns for ethanol blending in gasoline
zChange of fuel properties, e.g. distillation property, vapor pressure, etc.
zPhase separation, resulting from water contamination
zCompatibility with vehicle fuel system materials
etc.
2
Japan Petroleum Energy Center
RVP (Reid Vapor Pressure) increase with ethanol blending
80
RVP rise by about 7kPa with
3-10vol% of ethanol blending
RVP (kPa)
70
60
This phenomenon is due to decline
in strength of hydrogen bond and
azeotrope effect.
50
*3vol% of ethanol blend
is a permissible max.
limit by Gasoline Quality
30 Regulation in Japan
40
20
0
10 20
30 40 50
Ethanol (vol%)
Vapor pressure rise might
increase evaporative emissions
from motor vehicles.
The effects of ethanol blend on evaporative emission were
studied and compared with ETBE blend
3
Japan Petroleum Energy Center
Explanation about evaporative emissions from automobiles
zRefueling Loss
HC
HC
zHot Soak Loss (HSL)
Evaporated after engine turning off (for 1hour)
zDiurnal Breathing Loss (DBL)
Evaporated during long-term parking (for 24, 48, 72hours)
zRunning Loss (RL)
Evaporated during engine running
4
Japan Petroleum Energy Center
Contents
1. Introduction
2. Test vehicles & Fuels
3. Refueling Loss emission results
• Test method
• Comparison of vehicle type
• Effects of Ethanol / ETBE Blending
4. Running Loss emission results
• Test method
• Comparison of vehicle type, PFI and DISI
• Effects of Ethanol / ETBE Blending
5. Summary & Conclusion
5
Japan Petroleum Energy Center
Test Vehicles Specifications
Vehicle
A
B
Japan
2000
Japan
2000
1.5
2.0
Engine Type
L4
L4
Fuel System
PFI
DISI
50.0
60.0
Tank Location
Under Floor
Under Floor
Tank Material
Metal
Metal
No
No
Regulation
Displacement
Tank Capacity
(L)
(L)
Fuel Return
6
Japan Petroleum Energy Center
RVP level of test fuels
- RVP change with ethanol / ETBE blending 80
80
E3(RVP72)
75
70
RVP (kPa)
RVP (kPa)
75
BASE
65
60
E3(RVP65)
E10(RVP65)
70
65
60
55
55
50
50
0
2
4
6
8
0
10
ETBE8
BASE
2
4
6
8
10
ETBE (vol%)
Ethanol (vol%)
RVP increases by ethanol blend
7
RVP doesn’t change by ETBE blend
Japan Petroleum Energy Center
Contents
1. Introduction
2. Test vehicles & Fuels
3. Refueling Loss emission results
z Test method
z Comparison of vehicle type
z Effects of Ethanol / ETBE Blending
4. Running Loss emission results
z Test method
z Comparison of vehicle type, PFI and DISI
z Effects of Ethanol / ETBE Blending
5. Summary & Conclusion
8
Japan Petroleum Energy Center
Schematic of Sealed Housing for Evaporative Determination
(SHED) System & test procedure of refueling loss test
Fuel
Dispenser
Control
Unit
Fuel Temp
Controller
Fuel drain & 10% fill
Air Conditioner
THC
Anal.
Fuel Tank
Vehicle
車両
Temp control & Vehicle soak
10-12h
Refueling Test
SHED
Refueling unit
9
Japan Petroleum Energy Center
Comparison of refueling loss between
Japanese typical passenger vehicles
Refueling Loss (g/L)
2.5
Refueling Volume: 10 to 90% of vehicle fuel tank
Refueling Rate: 40L/min , Test fuel: Base Gasoline
Vehicle A
Vehicle B
2.0
95%
confidence
limit
1.5
1.0
0.5
0.0
30/35
35/40
30/35
35/40
Dispensed Fuel Temp (oC)/Ambient Test Temp (oC)
Refueling loss emissions don’t vary significantly according to vehicle type
between Japanese passenger vehicles, A (PFI) and B (DISI).
10
Japan Petroleum Energy Center
Effects of Temperature and Refueling Rate
on Refueling loss
Refueling Loss (g/L)
2.5
Vehicle A
Refueling Volume: 10 to 90% of vehicle fuel tank
Refueling Rate
40L/min
30L/min
2.0
1.5
1.0
0.5
0.0
25/30
30/35
35/40
25/35
30/40
Dispensed Fuel Temp (oC)/Ambient Test Temp (oC)
Despite the higher ambient temp, the amounts of
refueling loss are restricted by keeping fuel temp lower.
11
Japan Petroleum Energy Center
Experimental Refueling Loss (g/L)
Multiple Regression analysis for refueling loss
3.0
2.5
2.0
1.5
X = -0.01504*A + 0.059284*B - 0.00497*C
+0.021333*D - 0.87265
X: Refueling Loss (g/L)
A: Ambient Test Temp (oC)
B: Dispensed Fuel Temp (oC)
C: Refueling Rate (L/min)
D: Fuel RVP (kPa)
1.0
0.5
ETBE8(RVP65)
E3(RVP65)
E10(RVP65)
E3(RVP72)
R2=0.9648
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Estimated Refueling Loss (g/L)
There are no negative effects of ethanol-blended and ETBE-blended gasoline
on refueling loss other than RVP increase of the ethanol blended gasoline.
12
Japan Petroleum Energy Center
Contents
1. Introduction
2. Test vehicles & Fuels
3. Refueling Loss emission results
z Test method
z Comparison of vehicle type
z Effects of Ethanol / ETBE Blending
4. Running Loss emission results
z Test method
z Comparison of vehicle type, PFI and DISI
z Effects of Ethanol / ETBE Blending
5. Summary & Conclusion
13
Japan Petroleum Energy Center
Schematic of Sealed Housing for Evaporative Determination
(SHED) System & test procedure of running loss (RL) test
Engine Intake Air
Soak Area
Purge Air
Purge and load of the canister
an Apparatus
Room
THC
Anal.
Air Conditioner
Fuel drain & fill
40% full
Preconditioning drive
TB
DBL
Insert Door
RL, HSL
11mode + 3repeats of 10-15mode
@25 oC
Fuel temperature conditioning
35 oC within 4 hours
Running loss test
11mode + 3repeats of 10-15mode
@35 oC
14
Japan Petroleum Energy Center
Comparison of running loss (RL) between
typical market vehicles
0.4
Test fuel: Base Gasoline (RVP65kPa)
R L (g / km )
0.3
0.2
0.1
Evaporative emission
level of vehicles A is
very low
0
VehicleA
VehicleB
Vehicle B (DISI) shows significant high level of RL
compared to vehicle A (PFI).
15
Japan Petroleum Energy Center
Schematic of canister system
Adsorbed HCs are
Purge
purged by engine
vacuum during running
Engine
Canister
valve
Vapor
HC
adsorption
Flow Rate
Air
Canister Capacity
Fuel Inlet
Fuel Tank
Fuel Temperature
Fuel
(Evaporative emissions volume)
Fuel temperature, Canister capacity and Purge flow rate are
considered to be the key factors to control evaporative emissions.
16
Japan Petroleum Energy Center
Characteristics of test vehicles
Vehicle
A
B
Final Fuel Temp (oC)
42.5
48.0
Temp Rise (oC)
+7.5
+13.0
Canister Capacity (L)
0.9
0.9
Total Purge Flow Volume (L)
411
39
Vehicle A: Lower for final fuel temp and higher purge flow rate
Vehicle B: Considerably low for purge flow rate and relatively high
for final fuel temp
Vehicle B has disadvantages to control evaporative emissions
17
Japan Petroleum Energy Center
RL changes with ethanol blended gasoline
Increase of RL (%)
240
200
160
RL results with base gasoline are regarded as 0%
E3(RVP65)
RVP of each ethanol blended-gasoline
is adjusted to same level of base gasoline
(about 65kPa)
120
80
40
E5(RVP65)
0
-40
VehicleA
VehicleB
Even though RVP is same level, the increase of RL emissions with
ethanol-blended gasoline was significant in vehicle B.
18
Japan Petroleum Energy Center
Comparison of vapor pressure between base and ethanolblended gasoline at final fuel temp of each vehicle
BASE
Vapor pressure of the ethanolBlended gasoline is more
sensitive to temperature
increase than base gasoline.
Ethanol:3%
Vapor Pressure (kPa)
150
125
Vapor pressure rise of the
ethanol-Blended gasoline for
vehicle B was higher than that
of vehicle A.
100
75
RVP
50
Vehicle
A
Vehicle
B
25
20
30
40
50
60
O
Temperature ( C)
19
RL emissions from vehicle B
increased significantly with
ethanol-blended gasoline,
even though the RVP level of
test fuels were nearly equal.
Japan Petroleum Energy Center
Comparison of the ETBE blending effects on
RL with ethanol effects
Increase of RL (% )
240
200
160
120
80
40
0
RL results with base gasoline are regarded as 0%
E3(RVP65)
Ethanol blend
ETBE blend
RVP of each ethanol & ETBE blended
gasoline is adjusted to same level
with each base gasoline
(about 65kPa)
E5(RVP65) ETBE8(RVP65)
ETBE8(RVP65)
-40
VehicleA
VehicleB
RL emissions did not increase by ETBE blending even for vehicle B,
in contrast to the case of ethanol blending.
20
Japan Petroleum Energy Center
Comparison of vapor pressure change with temperature
between base and ETBE blended gasoline
BASE
ETBE:8vol%
Vapor Pressure (kPa)
150
Vapor pressure of ETBE-blended
gasoline is almost same with that
of base gasoline at each fuel
temperature.
125
100
75
RL emission level of ETBE-blended
gasoline is considered to be same
as that of base gasoline.
50
25
30
40
50
60
Temperature (oC)
21
Japan Petroleum Energy Center
Contents
1. Introduction
2. Test vehicles & Fuels
3. Refueling Loss emission results
• Test method
• Comparison of vehicle type
• Effects of Ethanol / ETBE Blending
4. Running Loss emission results
• Test method
• Comparison of vehicle type, PFI and DISI
• Effects of Ethanol / ETBE Blending
5. Summary & Conclusion
22
Japan Petroleum Energy Center
Summary(1)
As for refueling loss emissions,
zThere are no remarkable differences in refueling loss
level between conventional gasoline passenger vehicles
available in Japanese market, regardless to PFI or DISI .
zBoth ethanol-blended and ETBE-blended gasoline do not
significantly increase refueling loss emissions as long as
the RVP is controlled to the same level as conventional
gasoline.
23
Japan Petroleum Energy Center
Summary (2)
As for running loss (RL) emissions,
zThe level of RL emissions differs by vehicle type;
in the case of vehicles with higher final fuel temperatures
and low purge flows (DISI), the RL emissions level increases.
zFor vehicles with higher final fuel temperature,
the RL emissions level with ethanol-blended gasoline tends
to increase compared to base gasoline.
This is because vapor pressure of ethanol-blended gasoline
is more sensitive to temperature than that of base gasoline.
zWith ETBE-blended gasoline, the RL emissions level
does not increase in contrast to ethanol case.
24
Japan Petroleum Energy Center
Conclusions
zIn order to control evaporative emissions, from the view
point of fuel technology, it is imperative to control fuel RVP,
especially in the case of ethanol-blended gasoline.
zFrom the view point of vehicle technology, to reduce
RL emissions of ethanol blended gasoline, fuel temperature
control and higher canister purge flow rates are very important.
zETBE seems to be a more favorable fuel blendstock than
ethanol for the control of RL emissions.
To put commercial use of biomass-fuel as gasoline blend stock,
further study is required from both viewpoints:
vehicle emission control system and fuel properties.
25
Japan Petroleum Energy Center
End of Presentation
Thank You for Your Attention
Image of Refueling Loss
Air Vent Pipe
Vapor (Refueling Loss)
Fuel Inlet
Refueling Nozzle
Fuel
Tank
Dispensed Fuel
The effect of gasoline vapor being absorbed into the
dispensed fuel is considered to occur when there is large
difference between ambient temp and dispensed fuel temp.
This effect seems to be strengthened in case of higher
refueling rate.
27
Japan Petroleum Energy Center
Comparison of fuel temperature profile
Speed
B
45
A
40
Speed
35
30
0
300
600
900 1200 1500 1800 2100 2400
80
60
40
20
0
Speed (km/h)
Fuel Temperature (oC)
50
Vehicle A
Vehicle B
Time (sec)
28
Japan Petroleum Energy Center
40
Vehicle A
Vehicle B
30
Speed
20
10
0
Speed
0
300
600
900
80
60
40
20
0
Speed (km/h)
Purge Flow Rate (L/min)
Comparison of purge flow rate
1200 1500 1800 2100 2400
Time (sec)
Due to lean burn direct injection engine system, the intake manifold vacuum
of vehicle B is very low and thus purge flow rate is the smallest.
29
Japan Petroleum Energy Center
Effect of ethanol- / ETBE-blended gasoline on
Refueling loss
Refueling Loss (g/L)
2.5
Vehicle A
Dispensed Fuel Temp / Ambient Test Temp: 35oC / 40oC
Refueling Volume: 10 to 90% of vehicle fuel tank
Refueling Rate: 40L/min
2.0
1.5
1.0
0.5
0.0
BASE
(RVP65)
E3
(RVP72)
E3
(RVP65)
E10
(RVP65)
ETBE8
(RVP65)
Both ethanol- and ETBE-blended gasoline do not significantly increase
refueling loss emissions as long as the RVP is controlled to the same level.
30
Japan Petroleum Energy Center
Relationship between RL emission and vapor pressure
at final fuel temperature
Vehicle B
2.5
Normal Gasoline
Ethanol blend
RL (g/km)
2.0
1.5
1.0
0.5
0.0
80
85
90
95
100
105
Vapor pressure @ final fuel temp (kPa)
RL emissions depend greatly on the vapor pressure at the final fuel
temperature in vehicle B
31
Japan Petroleum Energy Center
Comparison of vapor pressure at final fuel temp
between vehicle A and C
BASE
Ethanol:3%
Vapor Pressure (kPa)
150
Driving(RL)
125
Refueling
100
75
50
25
20
30
40
50
60
O
Temperature ( C)
32
Japan Petroleum Energy Center
33
Japan Petroleum Energy Center
Effect of Ethanol on Compatibility with Metal Materials
SAE2005-01-3710
34
Japan Petroleum Energy Center
Effects of Ethanol on Elastomer Swelling
40 deg.C, 48Hr
Volume change , %
50
2FKM
3FKM
NBR
HNBR
40
30
20
10
0
0
10
20
30
40
Ethanol concentration ,vol%
出典:ブラジル大使館主催:公開シンポジウム(2001.11.5.)
35
Japan Petroleum Energy Center
General Properties
Ethanol
Gasoline
Formula
MW
O content (mass%)
Density
Boiling Point (℃)
RVP (kPa)
Water Solubility (mass%)
Small
Mixture
Net Calorific Value (kJ/kg)
Octane Number (RON)
Regular
Premium
36
Japan Petroleum Energy Center
Compositions of evaporative emissions - refueling loss
Vehicle A
Dispensed Fuel Temp / Ambient Test Temp: 35oC / 40oC
Refueling Volume: 10 to 90% of vehicle fuel tank
Refueling Rate: 40L/min
Composition (mass%)
C3
C9
C4+C5
C10↑
C6
Ethanol
C7
ETBE
C8
100
80
60
40
20
0
BASE
(RVP65)
ETBE8
(RVP65)
E3
(RVP65)
37
E10
(RVP65)
E3
(RVP72)
Japan Petroleum Energy Center
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