Biodiesel Technical Training Course

BIO 3.0: Biodiesel Vehicle Maintenance

and Performance

Presented by the National Biodiesel

Board

National Biodiesel Board

• The National Biodiesel Board (NBB) is the trade association for the U.S. Biodiesel Industry

• Receives funding from 3 sources:– Soybean Check-off program (i.e. farmers)– Government Grants and programs– Biodiesel Producer contributions

• Technical, Regulatory, Marketing and Lobbying• Over $100MM over last 15 years

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Today’s Topics

• Biodiesel Definition• Key Properties of Biodiesel • Fuel System, Air Intake, & Lubrication • Starting, Charging, Cooling, & Vacuum

systems• Exhaust & Emissions Controls• Resources

Learning Objectives

• Provide access to industry experts for more detailed questions and answers about biodiesel

• Introduce the National Biodiesel Board’s Diesel Technician Training program and the program resources to the audience

• Provide technical instruction on biodiesel’s impact towards engine performance and vehicle maintenance

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Learning Outcomes

• Be able to discern issues between normal diesel problems and poor quality biodiesel imposters or out-of-spec biodiesel when they hit the shop

• Be able to properly diagnose and make recommendations regarding biodiesel use and vehicle maintenance

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Biodiesel Defined

• Biodiesel, n. -- a fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats, meeting ASTM D 6751, designated B100.

• Biodiesel Blend, n. -- a blend of biodiesel fuel with petroleum-based diesel fuel designated BXX, where XX is the volume percent of biodiesel.• This tight definition was needed in order to secure vehicle,

engine and fuel injection equipment company support for biodiesel, as well as to secure ASTM specs

Biodiesel (B100) Attributes

• High Cetane (avg. over 50)• Ultra Low Sulfur (avg. ~ 2 ppm)• High Lubricity, even in blends as low as 1-2%• High Energy Balance (4.5 to 1)• Renewable, Sustainable, Domestically Produced• Increases overall fuel production capacity in

USA • Reduces HC, PM, CO in existing diesel engines

Enhanced Lubricity

Ultra-low Sulfur Diesel

0100200300400500600700800

0.0 1.0 2.0 3.0 4.0 5.0

Biodiesel Blend (%)

HFRR WSD (micron)

• Equipment benefits– Superior lubricity– B2 has up to 66%

more lubricity than #2 Diesel

• EPA required sulfur reduction in diesel

• No overdosing concerns

Cold Weather Performance

• Pure biodiesel does freeze faster than most petrodiesel• Your B20 supplier should provide blends of B20 that will

not cause any cold flow issues in the winter – Exactly the same way they do with #2 diesel fuel

• There are a variety of tools at the disposal of distributors to improve the cold flow operability of #2 petrodiesel and biodiesel blends– Blending with #1, cold flow additives, etc.

• B20 has been used successfully in climates below -20ºF

Biodiesel Fuel Stability

• The biodiesel specification contains parameters for insuring adequate fuel stability for normal applications

• The shelf life of biodiesel blends is recommended by NBB as 6 months

• Stability additives available on the open market

Solvency Effect

B20 & Under• Monitor filters, less than 2% need to be

changed• Mild cleaning effect• Storage tanks may need to be cleaned, or

keep extra filters on hand at start up• Housekeeping protocols for generic diesel

equally important prior to blending

Fuel System• Material compatibility is key for higher blends• Repair Fuel leaks to prevent impact to other systems!• From the fuel sending unit in tank to injectors-primary & secondary fuel filters-Fuel lines (sending & return)-High pressure or low pressure injectors- o-rings-transfer & injection pumps

Lubrication System

• Change oil as recommended by Engine manufacturer

• Use OEM recommended engine oil• API, CI rating• Regular oil analysis maintenance program• Inspect dipstick for biodiesel smell

Lube Oil Contamination

• Current ongoing research, SAE CI Engine Performance with Alternative Fuels, 2008

• A concern of engine manufacturers.• Same mechanism for the oil dilution for heavier fractions of

diesel fuel as for biodiesel.• Due to high boiling point of biodiesel, the fuel is slower to

vaporize after injection into the cylinder.• Remaining compounds will be deposited on the cylinder wall

where they can be pulled into the crankcase by the normal scraping action of the piston's oil control rings.

• Light Duty issue, 2009+

Air Filtration

• In a diesel engine, the amount of air remains constant while fuel amount is varied for speed and power control

• Lean mixture at idle (80:1)• Rich mixture under load (20:1)• Mass Air Flow (MAF) sensor • VW TDI EGR/ Intake design• Diesels thrive on air, lots of it, any air restriction will

cause performance problems

Starting & Charging System

• Properly charged battery• Operating Starter or Alternator• Fouled glow plugs can cause hard starting• Glow plugs factory recalls • Dual Battery system

Vacuum System

• Diesel maintenance issueCheck your vacuum lines-

• Leaky & Inoperative vacuum system can affect:

Brakes, Fuel shutoff, & transmissions

Cooling System

• Cooling system helps your engine warm up & cool down

• Operating at optimum temperature helps fuel economy & engine life• Cooling system hoses are not always biodiesel

compatible, repair fuel leaks immediately to prevent damage to other systems

Exhaust & Emissions Controls

• EGR: Exhaust Gas Recirculation• Catalytic converters• DPF: Diesel Particulate Filters• DOC: Diesel Oxidation Catalyst• SCR: Selective Catalytic Reduction

(Urea) • Emissions regulations dictating changing

engine and fuel injection design

Are you Smoking?

• Black smoke: injectors, air inlet restriction, engine timing, internal engine timing, injection pump failure

• Blue Smoke: insufficient fuel, contaminated fuel,High or low oil consumption, air in the fuel

• White smoke: bad glow plugs, plugged return fuel line, insufficient fuel supply, low compression, air in fuel, injector or pump problem, engine timing

• White smoke can be normal in cold weather before engine warms

Miscellaneous

• NOx Emissions see:NREL’s “NOx solutions for Biodiesel”• Cold weather Operation• Timing belts & chains- replace at

recommended intervals• Educate your fellow technicians• Bosch & Stanadyne & FIE/OEM statement

Biodiesel Performance:Some Examples of Lab Durability

Studies

1000 Hour Durability B20

The objective was to operate the engine for 1000 hr using B20 biodiesel fuel, and do a comparative analysis with engines that have operated under the same type of conditions using #2D diesel fuel.

hr

0 25 50 125 1000

Accelerated, high-load durability cycle

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Test Engine

• Cummins prototype 2007 ISL• Six cylinder 8.9 liter• Rated power of 330 BHP• Peak torque of 1150 ft•lb at 1300 rpm• Diesel Oxidation Catalyst (DOC)• Diesel Particulate Filter (DPF)• Post injection (in-cylinder) for active regeneration• Variable geometry turbocharger• Exhaust gas recirculation (EGR) with cooler• Cummins fuel injection system

Test Cycles

• Durability Testing• Accelerated• High-load• Transient cycle • Varying load and speed• Cycle repeated for 1000 hr

• Emissions Testing• Federal Test Procedure (FTP)• One cold start transient FTP test• Three hot start transient FTP test• One SET Ramped Modal Cycle

High IdleLow Idle

Peak Torque

Peak Power

>70% of durability cycle at full load

Durability & Emission Results

• Approximately 17,000 gallons of B20 biodiesel fuel was used during the durability test.

• Test went well and was successful. There were no biodiesel related failures during the test, and no reported significant changes in performance of the engine.

• Engine performance was essentially the same when tested at 125 & 1000 hr of accumulated durability operation.

• Emission results indicate that THC, CO, and PM levels were not significantly different between the B20 and ULSD. • The emission-grade B20 test resulted in ≈6% higher NOx (within

expected range)• Fuel consumption was observed to be ≈3% higher than the 2007

certified ULSD test (within expected range).

Top of cylinder head No sludge deposits

Bottom of cylinder head Deposits comparable to #2D

Intake Valves Exhaust Valves

Results are typical for this type of test with #2D diesel fuel

Overhead Components

Power Transfer Components

Component CommentsCranckshaft Gear Meets rebuild spec

Cam Gear Meets rebuild spec

Cam Bushing Meets rebuild spec

Fuel Pump Gear Meets rebuild spec

Cranckshaft Meets rebuild spec

Lower & Upper Bearings

Normal wear

Connecting Rod Meets rebuild spec

Connecting Rod Bushing

Meets rebuild spec

During teardown, the crankshaft was found to be in very good condition, and results were comparable to #2D diesel fuel test.

Power Cylinder Components

Component Comments

Piston Normal light wear and deposits.

Cylinder Liners Normal light wear.

Top rings Normal uniform face wear. Top and bottom side look typical.

Middle rings Normal face wear. Top and bottom sides OK, and light carboning.

Oil rings Looked good. Very little wear.

Crosshatch visible in all six cylinders.

Results comparable to #2D diesel fuel test.

Ring GroovesAnti-Thrust Side

Cylinder 1

Top PistonPiston Bowl Front

Cylinder 1

Minor staining

Cooling and Lube Components

Component Comments

Oil pump No issues

Oil cooler head No issues

Oil cooler cover No issues

Oil pressure regulator/bypass

No issues

Piston cooling nozzles

No problems due to B20.

Oil Pan Normal

Oil suction tube Gasket showed good imprint of seal

Turbo coolant/oil lines

Normal

There were no failures found on the cooling and lube components. The wear and deposits found on the parts were normal and consistent with findings found on parts that ran with #2 diesel fuel in similar tests.

Bottom (Oil) Piston Rings

Cylinder 1 Top

Cylinder 6 Bottom

Air Handling Components

Component Comments

Exhaust Manifold No issues.

EGR Cooler No cracks, light coating of soot on inlet and outlet tubes. No soot in inlet diffuser. Findings good overall.

EGR Valve Looked good. Normal soot accumulation.

EGR gaskets, hoses, tubes, shield, mounting plate, crossover

No issues found due to running with B20.

Carbon deposit layer was generated on the passage and inside parts of the EGR valve, but thickness was very thin and condition was dry which is normal for this durability test.

Aftertreatment Components

Component Comments

Diesel Oxidation Catalyst (DOC)

Looked good. No face plugging.Blockages found appeared like debris and substrate material. Debris was analyzed under Electron Dispersive Spectroscopy (EDS), and all debris found is expected in a typical DOC after 1000 hr of operation, whether fueled with ULSD or biodiesel.

Diesel Particulate Filter (DPF)

Inlet face showed signs of ash build up, but similar to diesel fuel for this type of test. Outlet looked good with no signs of soot.No failure found.

Inlet and outlet section

Looked good.

Gaskets Looked good.

Fuel System Pictures

Stage 1 Plunger Needle

No marks on needle surface or the edge.

Plunger Needle – Top View

Some slight staining.

Stage 2 Plunger Needle has some wear, but normal for this type of aggressive test.

Plunger Orifice not clogged with oil sludge or deposits

Fuel System ComponentsRail and fuel lines Rail – No abnormal wear.

End Fitting – No unusual wear. HP Fuel Lines – No visible structural deterioration or cracks observed.

Mechanical Dump Valve (MDV)

No unusual wear, deterioration or sludge buildup observed on plungers, plunger seats or orifice.1) Stage One Plunger – No wear visible on the needle surface or the edge. Some slight staining seen on plunger base.2) Stage Two Plunger – Some wear, but normal. Plunger orifice not clogged with oil sludge or deposits.

Injectors Injector performance test and photos indicate that the injectors were consistent with injectors that ran with #2D diesel fuel.

Soft Lines No visible damage to any section of the internal wall of the used fuel tubes indicating that the tubing liner material is resistant to the B20 temperatures and pressures during the engine performance test.

Overall There were no signs of severe or aggressive corrosion pitting damage on any of the surfaces.

Summary

• A Cummins 2007 prototype 8.9 liter ISL diesel engine equipped with DOC, DPF, VGT, and EGR with cooler was operated successfully at SwRI using a high-load accelerated durability cycle for 1000 hr with a B20 blend of soy-based biodiesel and ULSD.

• During the durability testing, no biodiesel related failures occurred.

• Engine performance was essentially the same when tested at 125 and 1000 hr of accumulated durability operation. Emissions measurements indicate the HC, CO, and PM were not significantly different between the B20 and ULSD tests, and NOx increased with B20 fuel. Fuel consumption also increased with B20 fuel.

• A thorough engine teardown evaluation of the overhead, power transfer, cylinder, cooling, lube, air handling, gaskets, aftertreatment, and fuel system parts was performed.

• There were no failures found on the engine components that were directly attributable to running biodiesel B20.

• The wear and deposits found were normal and consistent with findings from parts that ran with #2 diesel fuel in similar tests.

Diesel Emission Reductions

Fuel technology

Combustion technology

Aftertreatment technology

Fuel system technology

Better understanding of combustion

Alternate Fuels (Biodiesel)Low sulfur De-NOx

DOC

PM trap

Rate controlHigh pressure Multi-injection

EGR technology

Others

Control technology

Technology Pathway

Sources for Filter Clogging:Petrodiesel and Biodiesel

Exposure to AirExposure to Air

• Enters through vent pipes and contains large amounts of moisture.

• Generally displaces the fuel as tank is emptied.

• It is not practical to keep air from entering the tank.

• Will increase the oxidation of fuel.

• Do not store fuels for long periods of time in partially empty tanks without stabilizers.

• Consider desiccant dryers.

Microbial Growth

• Microbes are bacteria or fungus that live and propagate in fuel at the fuel/water interface.

• Water needed to live—no water, no bugs.

• Hydrocarbons in petrodiesel or biodiesel provide the food and the water provides the oxygen.

• This environment is needed for living, growth, and reproduction.

• The filters with microbial contamination often had an odor different from the normal fuel smell.

Water Contamination

• ULSD reaches water saturation at approximately 200-300 ppm. More settles to the bottom.

• NREL B20 survey data: same water saturation level as petrodiesel. More settle to the bottom

• B100 can hold more water, up to 1200 ppm

• Still very small—0.12%, on the same order as gasoline can hold water. Un-dissolved water settles to the bottom like it does in petrodiesel tanks.

• While higher than petrodiesel, biodiesel is not water loving (i.e. hygroscopic) like ethanol is. Most people do not understand this fact.

Icing of the filter

• When there is excess free water in fuel, it can form ice on the filter and cause filter plugging in cold temps. A filter which has been plugged but is clean and new at room temperature indicates that icing is the likely cause.

• Since the temperatures of engines are warm, any moisture picked up within the engine can be brought back to the fuel lines. This moisture can freeze overnight in low ambient temperatures.

Free water

Sediment/Rust build-up

• Some of the filters had solid sediment within the folds and solid particles in the filter casing.

• Sediment present in the fuel or rust particles from within the engine can collect over time and plug the filter even when there are not necessarily problems with the fuel.

Sediment/Rust build-up

Paraffin Wax

• High level of paraffin material could be from the way ULSD is processed.

• When the temperature of the fuel is at or below its cloud point, paraffin material will precipitate out and collect on the bottom of the tank.

• When warmed to room temperature the paraffin wax will turn back into liquid.

• Paraffin build-up does not come from biodiesel fuel.

Paraffin Wax

Oxidation

• Filters with a black and shiny surface but no microbial growth odor or gel or sediment indicate they may be plugged by oxidation build-up.

• Because many newer engines run at higher temperatures, there may be a black “asphaltene” petrodiesel type material collecting on the filter.

• This phenomenon has been seen all around the country, often in newer engines.

Oxidation

• Petrodiesel does not have an oxidation specification, while B100 and B6 to B20 specs already do.• Biodiesel can also oxidize, but oxidized

biodiesel manifests itself in acid numbers which are out of spec• The acid number for biodiesel will go out of

spec before filter clogging occurs

Monoglyceride Build-up

• The next filter tested positive for high concentrations of saturated monoglyceride material—an out of spec or ‘imposter’ biodiesel.

• Monoglyceride is one substance that can precipitate out of fuel if not within spec

• Monoglycerides do not turn back into a liquid at room temperature

• Can be distinguished from diesel by its brownish, butterscotch pudding type of appearance

Un-reacted Off-spec Biodiesel: Saturated Mono-glyceride

Troubleshooting Checklist

• Microbial Growth – Exposure to air and water

• Icing of Filter – Excess water in tank

• Oxidation – Hot fuel return to fuel tank

• Monoglyceride Build Up – Off specification

• Paraffin Wax – Temperature at or below cloud point

Steps to Maintaining Fuel

• Store Fuel in Clean, Dry Dark Environment• Keep Tank Topped off to eliminate head space• Monitor hoses, fill/vapor caps, gaskets for leaks• Storage in on-site tanks should be limited to less

than 6 months.• Once a year send your fuel to lab to be tested for

microbial contamination

Biodiesel Use & Handling

• Refer to the Biodiesel Use & Handling Guidelines available on the Biodiesel Training Toolkit and at: http://www.nrel.gov/vehiclesandfuels/pdfs/43672.pdf

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Using Biodiesel:

Biodiesel Use and Handling Guidelines:• Ensure the biodiesel meets the ASTM specification for pure biodiesel

(ASTM D 6751) before blending with petro diesel. • Purchase biodiesel and biodiesel blends from companies that have

been registered under the BQ-9000 fuel quality program when possible.

• Ensure your biodiesel blend supplier provides a homogenous product.

• Avoid long term storage of B20 and higher blends to prevent degradation. Biodiesel should be used within six months.

• Prior to transitioning to B20, it is recommended that tanks be cleaned and free from sediment and water. Check for water and drain regularly if needed. Monitor for microbial growth and treat with biocides as recommended by the biocide manufacturer.

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Using Biodiesel:

• Biodiesel and biodiesel blends have excellent cleaning properties. Fuel filters on the vehicles and in the delivery system may need to be changed more frequently upon initial B20 use; after that, system runs cleaner with no issues.

• Be aware of the biodiesel blend’s cold weather properties and take appropriate precautions. When operating in winter climates, use winter blended diesel fuel. Make sure the biodiesel blend cloud point is adequate for the geographical region and time of year the fuel will be used.

• Perform regularly scheduled maintenance as dictated by the engine operation and maintenance manual.

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Biodiesel and Aftertreatment Systems

Biodiesel is compatible with Diesel Particulate Filters, and has some distinct advantages:• Lowers regeneration temperatures• Less engine out particulate matter• May provide increased performance and decreased maintenance vs.

ULSD alone• May provide increased fuel economy

Regeneration mode is important• Late in-cylinder injection may cause increased fuel dilution of engine

oil and limit the level of biodiesel that can be used (i.e. B20 or B5)• Most US heavy duty applications use exhaust stream fuel injection

which is compatible with B20, perhaps higher blends• Some light duty OEMs recommend max B5 at present

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B20 vs. Diesel: In the shop

• With in-spec B20 and lower, the issues you can expect to see in your shop are the same as you will see with petrodiesel

• Except:– Expect to see fewer lubricity related issues– Expect to see fewer problems with after-treatment– Filter related issues may be related to cleaning effect upon

first use, or are likely normal diesel issues or out of spec or imposter biodiesel

– Less black smoke from exhaust!

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Biodiesel Resources

www.biodiesel.org•Biodiesel Training Toolkit

•News Releases & Information Resources

•Technical Library, Spec Sheets & Videos

•OEM Warranty Positions on Biodiesel

• U.S. Diesel Vehicle List

www.BQ-9000.org •Listing of BQ-9000 Certified Companies

www.biotrucker.com•Listing of BioTrucker retail sites

www.biodieselautomotive.org•Dedicated to information exchange for biodiesel & diesel technicians

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Thank You!Questions…?

Rachel BurtonOEM Diesel Technician Training Programwrenchwench@blast.comTel: 919-444-3495

Call NBB at 1-800-841-5849Visit www.biodiesel.org

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