Biofuels – Benefits and Challenges William Woebkenberg - US Fuels Technical and Regulatory Affairs Mercedes-Benz Research & Development North America 2013 SAE Government & Industry Conference
Benefits and Challenges in fuel technology
1. DIESEL ASPECTS
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U.S. Biodiesel Production by Calendar Year
Volume in Gallons
US-Diesel Fuel Consumption (on road): 60 bn gallons
1,200,000,000 1,000,000,000
1.1 Billion ==> 3%
Economic Downturn RFS2 Uncertainty Lapse of Biodiesel Tax Credit
800,000,000
700 Million 545 Million
600,000,000
450 Million
400,000,000
1
2005
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315 Million
250 Million
112 Million
200,000,000 0
2012+: RFS-2 Implemented Biodiesel Blenders Tax Credit Extended
2
2006
3
2007
4
2008
5
2009
6
2010
7
2011 Page 3
Daimler preference: B5 with nationwide coverage instead of B20 mandates in single states NBB forecast for biodiesel volume in 2020: B7,5 average nationwide / currently B2.3 at today production volumes 2013 SAE Government & Industry Conference
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Daimler Supports US National B5 Blend
Diesel fuels Main Grade
2010
2011
Ext. Main Grade
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2012
2013
2014
2015
2016
2017
B5 (5 %v/v max for reliable vehicle operation)
2018
2019
2020
B5 + X; X additional HVO or BTL 5% up to 15% depending on availability
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Diesel powertrain is Key Enabler to GHG Compliance • 30-40% fuel economy over similar size GTDI powertrain more than offsets greater carbon intensity of petroleum diesel. • Superior low rpm torque/average horsepower in typical driving range as well as refined NVH associated with common rail technology ensure customer acceptance of diesel technology. • Renewable fuel aspect of biodiesel (FAME) is compelling but…..
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Key issues in quality of Bio-Diesel (FAME): • Lower stability against aging compared to conventional diesel:
Generation of acid corrosion of the hydraulic systems, sludging of engine oil
Generation of polymers sticking due to deposits in the high pressure system; could also arise in the electric lift pump • Production induced pollution:
Sodium/Calcium/other metals with Fatty Acids form soaps deposits in the injector and plugging of the fuel filter / particulate filter • High boiling range: Oil dilution and in the extreme case oil siltation • High miscibility with water promotes organic life forms at fuel/water interface
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Bio-Diesel and Micro-Organisms • Bacteria and fungi can survive in a fuel-water boundary layer, i.e. in underground tanks or in gas stations under poor housekeeping conditions • With higher Bio-Diesel content, the risk of micro-organism growth increases due to less chemical stability and higher water solubility in BioDiesel • Depending on the type of micro-organisms, acids or bacteria sludge is formed • This can lead to heavy corrosion or filter / component plugging
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Oxidation Stability is Important • If oxidation stability of Bio-Diesel is too low, acids and polymeric sludge can be formed • High temperatures and contact with oxygen and/or catalytic surfaces (copper, brass) lead to increasing oxidation • Oxidized biodiesel can cause heavy corrosion and deposits and can deteriorate the engine oil
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Biodiesel has a Shelf Life
Start IP=6h per ASTM D7467
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Many Plugged Fuel Filters with B20 Vehicle Type/ Number
GL Class/ 1554
GL Class/ 1554
GL Class/ 1555
ML Class/ 1559
R Class/ 966
S Class/ 3630
Test location
Burton, MI
Los Angeles, CA
Corpus Christi, TX
Burton, MI
Corpus Christi, TX
Denver, CO
Test profile
City/HW
City/HW
City/HW
Highway
Highway
City/HW
Mileage with B20 [mi]
52,000
67,605
52,000
50,000
50,000
119,303
Fuel filters plugged
2
3
5
3
9
1
Average mileage per filter [mi]
26,532
22,361
10,396
16,713
5,534
-
MIL warnings
4
4
10
1
9
5
DPF regeneration abnormities
no
yes
yes
no
no
yes
Maximum Oil Dilution [% m/m]
6
33
16
4
3
13
Increased DPF ash content
no
yes
yes
no
no
Under investigation
Injector coking/deposits
no
yes
no
no
no
no
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Biodiesel Quality Must Improve in US. Quality management system • Implementation of a quality control system for the final biodiesel blend at gas stations is required. • Biodiesel production facilities have to be accredited at least acc. to BQ-9000 of the National Biodiesel Board and have to follow their quality definitions for the production process. Main Specification Improvement Needs • Increase of oxidation stability: Increase in oxidation stability within B100 (ASTM D6751) to 8 h and within B20 (ASTM D7467) and B5 (ASTM D975) to 20 h. Definition of biodiesel purity (ASTM D6751). Inclusion of a minimum content of fatty acid methyl ester (96,5 % m/m) and limitation of mono- (0,8%), di- (0,2 %) and triglycerides (0,2%). Improvement of cold soak filtration test and reduction of metal content limit is required.
Adoption of ASTM (bio)diesel standards must be mandatory down to at least the distribution level for all states in the USA.
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Benefits and Challenges in fuel technology
2. GASOLINE ASPECTS
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Mercedes-Benz Pioneered Direct Injection 1954: 300 SL First passenger car direct injection
2009: DE-Rollout in four cylinder engines
2006: CLS 350 CGI: worlds first spray guided lean stratified direct injection
2010: Rollout in all vehicle platforms with 6- and 8-cylinder engines
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3rd Generation Direct Injection: Stratified Lean Burn Spray Guided Injection with Multiple Injection Patterns and Multiple Ignition
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Advanced Fuel Injection = Improved Power and Lower Emissions
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Advanced Fuel Injection – Improved Fuel Consumption Everywhere
specific fuel consumption for 2000 1/min
specific fuel consumption [g/kwh]
= variable valve lift
- stratified combustion - HOS - variable valve lift, Lambda 1
stratified
homogeneous
IMEP [bar] 2013 SAE Government & Industry Conference
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More Octane Enables More Power and Efficiency from Smaller Engine
Octane means engine can be made smaller and more fuel efficient while meeting customer expectations for power and torque
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E20 and E85 Optimization Provides CO2 Gains FVV Project “Future Fuels for Gasoline DI-Engines”
CO2 benefit [%) 20 10
E20 Splash Blend RON 102
E85 Summer 4,4
Ford Focus ST Curb weight: 1392 kg Transmission: 6-speed manual
Change [%]
3,1
Vehicle Data:
FE penalty (%)
0 -4,3
-10 -20 -30 -40
-36,4
Gasoline/Ethanol blend E20 with RON 102 is a good compromise between CO2 benefit and fuel economy penalty 2013 SAE Government & Industry Conference
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E25 Reduces HC Emissions
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E25 Reduces CO Emissions
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E25 Makes Better Power
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Daimler Supports Mid-Blend Ethanol Fuels with Increased Octane Gasoline fuels 2010
2011
2013
2014
2015
2016
2017
2018
2019
E10 (from 2010 applicable for all new models)
E20-E25 with octane increase
E10 in US/E5 in EU (EU needed until at least 2016)
E10
Main Grade Protection Grade (Legacy Fleet)
2012
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2020
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Current Gasoline Blends and Consumption Current Fuel Pool* Regular
Mid Grade
Premium
87 AKI – E10
89 AKI – E10
91 AKI – E10
*excluding 85-86 AKI, 93-94 AKI, E15 and Flex-Fuels Current Blend Consumption Mix*
86%
6%
*based on www.eia.gov 2011 annualized sales volumes and blend consumptions
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8%
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Proposal – Reallocation of Current Ethanol Pool into Tier III-Dedicated High Octane Fuel Tier III Ethanol Pool Scenarios Regular
Mid-Grade
Premium
Tier III
Tier III Octane*
7
X
10
30
101 RON
8
X
10
25
100 RON
8.5
X
10
20
99 RON
9
X
10
15
98 RON
*based on 92 RON Premium BOB
Assumptions: • Based on 2 tank retail system • Mid-Grade eliminated • Premium is blended from Tier III and Regular • Tier III volume initially is equal to Mid-Grade volume eliminated 2013 SAE Government & Industry Conference
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Proposal – Reallocation of Current Ethanol Pool into Tier III-Dedicated High Octane Fuel Tier III Ethanol Pool Scenarios Regular
Mid-Grade
Premium
Tier III
Tier III Octane*
7
X
10
30
101 RON
8
X
10
25
100 RON
8.5
X
10
20
99 RON
9
X
10
15
98 RON
*based on 92 RON Premium BOB 1% additional gasoline volume for E9 regular + Tier III gasoline volume for E15 blend recovers the 6% gasoline volume previously occupied by Mid-Grade fuel.
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Proposal – Reallocation of Current Ethanol Pool into Tier III-Dedicated High Octane Fuel Tier III Ethanol Pool Scenarios Regular
Mid-Grade
Premium
Tier III
Tier III Octane*
7
X
10
30
101 RON
8
X
10
25
100 RON
8.5
X
10
20
99 RON
9
X
10
15
98 RON
*based on 92 RON Premium BOB 3% additional gasoline volume for E7 regular + Tier III gasoline volume for E30 blend increases 6% gasoline volume previously occupied by Mid-Grade fuel.
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Advantages – Reallocation of Current Ethanol Pool into Tier III-Dedicated High Octane Fuel • As Tier III vehicles increase, the legacy Regular fuel will provide the gasoline and ethanol volume to supplant Tier III fuel requirements. • Provides mechanism for increased octane desired by most OEMs in their quests for optimized GHG and FE. • As ethanol pool increases, the blend level of the Tier III can be maintained (or increased, depending on initial level). • Provides EPA with reasonable Tier III Certification Fuel starting point for ethanol blend level and also provides a real ethanol usage rate against which future increases in Certification Fuel blend levels can be gauged.
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Summary • Daimler endorses a national B5 biodiesel blend standard and incorporation of oxidation stability specifications in D975. • Increased octane with midblend ethanol fuels is key enabler to simultaneously achieve GHG compliance with high customer satisfaction. • Implementation of retail midblend ethanol fuels does not require increase in ethanol pool – just reallocation. • The correct fuel for optimized performance is achievable with today’s resources.
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