canadian diesel fuel

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CANADIAN

DIESEL FUEL

CURRENT TOPICS

Dr. Andy Pickard

Senior Advisor, Fuels

Petro-Canada

North American

Council of

Automotive Teachers

2001

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DIESEL FUEL TOPICS

• Fuel Standards and Specifications;Canadian & American; OEM

• Emissions Issues

• Fuel Qualities <=> operations / problems

• Miscellaneous Diesel Fuel Issues

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CAN/CGSB-3.6 & -3.517

• National Standards of Canada for Regular Sulphur Diesel Fuel and Automotive Low Sulphur Diesel Fuel.

• Consensus standards

• Provinces must legislate for legal standing

• Minimum standard in practice.

• [www.pwgsc.gc.ca/cgsb]

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U.S. Diesel Fuel Standard

• ASTM D 975 - consensus standard– RSD & LSD

• State Responsibility

• California Diesel Fuel: “CARB Diesel”

• [www.astm.org]

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OEM FUEL SPECIFICATIONS

• Individual OEM companies may spell out fuel requirements

or recommendations.

• World Wide Fuel Charter

– EMA, AAM; JAMA; ACEA

– 4 categories of diesel fuel

– www.engine-manufacturers.org

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EMISSIONSEMISSIONS

EMISSIONS

• Driver: Air quality in urban areas.

• Particulates & Nitrogen Oxides (NOx)

• Forcing most engine and fuel changes.

• On-highway versus off-highway.

• Fuel: low sulphur & ultra low sulphur

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EMISSIONSEMISSIONS

EMISSIONS

• Major engine changes

– electronics

– higher fuel injection pressures

– timing changes / more soot

– EGR

– NOx catalysts and particulate traps

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IMPACTS on FUELS

• Electronics: hotter fuel; thermal stability;

fire safety issue.

• Injection pressure: lubricity / wear.

• Soot: lighter fuel / lower aromatics.

• EGR: --

• NOx catalysts: “no” sulphur.

• Particulate traps: lighter fuel / lower aromatics.

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FUEL QUALITIES:

OPERATIONS & PROBLEMS

Individual specification requirements

will be discussed, with implications

for diesel engine operations or

problems.

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FUEL QUALITIES:

OPERATIONS & PROBLEMS • CLEANLINESS !!!!

• Clean & Dry is critical, and is the most important single quality requirement!!

• Dirt / particles will plug filters, restrict fuel flow / power, and lead to wear in pumps and injectors.

• Water can cause rusting, corrosion, erosion, wear & catastrophic failure.

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CETANE NUMBER

• Diesel fuel combustion quality

• Higher cetane = quicker combustion

( shorter ignition delay )

• Cetane number = engine test result.

• Cetane index = calculation to predict cetane number.

• No correlation to fuel density.

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CETANE NUMBER

• 40 cetane number is minimum standard in North America ( typically 41 - 46 ).

• Higher cetane is desirable, but expensive.

• Cetane quality effects cold starting:– white smoke– warm-up (smooth or rough)– noise level

• Cetane requirement drops when engine hot.

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SYNCRUDE: OIL SANDS

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SULPHURin Diesel Fuel

• Organic sulphur compounds in crude oil.

• Regular (high) sulphur diesel = < 0.5 % S

( RSD, <5,000 ppm sulphur )

• Low sulphur diesel fuel = < 0.05 % S

( LSD; < 500 ppm sulphur )

• Ultra low sulphur diesel fuel = < 15 ppm S

( ULSD, June, 2006 )

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SULPHURin Diesel Fuel

• Sulphur in diesel fuel: burns to form SOx

• Corrosive to engine and exhaust system

SOx + H2O ---> H2SO3, H2SO4

• Air pollutant

• increases particulates

• degrades engine oil

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LOW SULPHURin Diesel Fuel

• Lower particulate emissions

• Lower SOx emissions

• Less engine / exhaust corrosion

• Less engine oil degradation(longer oil drain or better quality oil)

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LUBRICITY

• The ability of fuel to lubricate parts of fuel systems (pumps and injectors).

• Most fuels have good lubricity.

• Low lubricity fuels require lubricity additive in Canada (but not in U.S.).

• Laboratory lubricity tests are poor, and may not show the presence of additives.

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LUBRICITY

• Rotary and distributor pumps are most vulnerable.

• Unit or in-line units (which are oil-lubricated) are less effected by fuel lubricity, and more likely to be ‘gummed’ by excessive lubricity additive or reaction of additive with engine oil.

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VISCOSITY

• The “flow” property of diesel fuel;

• Minimum and maximum limits;

• Effects:nozzle spray pattern & droplet size;

“slippage” past pump;

possible filter restriction;

lubricity / wear.

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DENSITY: ENERGY CONTENT

• kg / L @ 15 ºC; typically 0.855 kg / L

• Energy content is related to density:

• Higher density = higher energy content

• Better fuel economy or higher power

• Total range only about 7 % in energy(0.800 to 0.875 kg / L)

• Typically < 2 % variation winter to summer.

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API GRAVITY(Obsolete term)

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TYPICAL TRUCK TERMINAL

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LOW TEMPERATURE PROPERTIES

• Cloud point normally used.

• Obsolete term: pour point.

• “2.5 % low end design temperature”(2.5 % of hourly temperature readings are lower than the design temperature.)

• Not required in U.S. D 975.

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DIESEL FUEL NAMES

• Names related to temperature:• Seasonal diesel fuel - seasonally adjusted.• Identified by Celsius cloud point.• Obsolete names: Diesel 40 or P-40

negative Fahrenheit pour point: -40 ºF.• Other names: Arctic Diesel / No. 1 Diesel /

Diesel 50 / “Diesel Light”,

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LOW TEMPERATURE PROBLEMS

• Icing: most common winter problem;ice crystals or layer of ice

plug fuel filter.

Note: engine may run for a while before stalling.

• Actions: change filter / drain water when warm; change fuel for winter fuel.

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WATER & ICE

• No free water, however• No limit on dissolved water.• Solubility of water in diesel fuel

decreases as the temperature drops.• Excess water separates as a haze or as

ice crystals, which cause fuel filter plugging.

• Action: drain any water while fuel is hot.

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LOW TEMPERATURE PROBLEMS

• Waxing or gelling: rare problem.

Wax crystals separate below cloud point and plug filter; eventually fuel ‘gels’ and goes solid.

Action: Warm up & change fuel; replace fuel filter.

(It takes a lot of kerosene to ‘cut’ waxy fuel!)

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LOW TEMPERATURE PROBLEMS

• Fuel flow restriction:

Symptom: engine runs but does not develop full power.

Causes: fine filtration; partly plugged filter; high viscosity fuel.

Actions: replace filter / use higher porosity filter; change fuel.

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DISTILLATION

• Boiling range of diesel fuel.

• Higher boiling (heavier) components increase soot and deposits.

• Only real “choice” is between Type B (No. 2 - heavier fuel;

seasonal diesel fuel) and Type A (No. 1 - lighter fuel).

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FLASH POINT

• The temperature of the fuel at which the vapours will burn when ignited with a spark or flame.

• Minimum +40 ºC; typically +50 to +70 ºC.

• Safety issue; not a diesel engine issue.

• Auto-ignition: 225 ºC

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HIBERNIA

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ELECTRICAL CONDUCTIVITY

• Safety issue: Canadian diesel fuels must have suitable conductivity to dissipate static electrical charges that may develop during pumping.

• Minimum 25 pS/m; typically > 100 pS/m

• Not a requirement in the U.S.

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OTHER REQUIREMENTS

These specification requirements are usually “non-issues”:

• Copper corrosion

• Acidity (total acid number)

• Carbon residue

• Ash

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MISCELLANEOUS

• “Bad Fuel”: usually the sign of a mechanic who does not know what’s wrong!

• Identify the real issue: e.g. dirt, water.

• Differentiate between symptoms and causes.

• Talk to local fuel suppliers!

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MISCELLANEOUS

“Bad Fuel” continued:

• When there is a genuine fuel quality problem, there are usually many vehicles effected.

• When a single vehicle is effected, it may be due to dirty or contaminated fuel in that vehicle, but not to ‘all fuel’.

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HARMONIZATION

• Harmonization of fuels:

Canada will follow U.S. fuel developments in order to benefit from lower emissions from new engine designs.

e.g. 15 ppm ULSD “at point of sale” for on-highway diesel fuel.

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QUALITY

• Quality Control / Quality Assurance

• Many refineries and laboratories are now following ISO 9000 practices to ensure quality products.

• Still work to be done on quality practices in distribution and at point-of-sale.

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QUALITY

PROBLEMS

• # 1 issue is cleanliness: clean & dry!!

• # 2 issue is water / ice at low temperatures.

• All other fuel-related problems are minor by comparison.

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INVESTIGATION of COMPLAINTS

• What is the problem? What was really observed, not possible causes.

• When did it start?

• Where is the problem?

• Where is the problem not occurring?

• Test possible causes for consistency.

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HEALTH & SAFETY

• Use normal ‘good hygiene’ practices in handling diesel fuel:

• Minimize skin contact.

• Remove any fuel-soaked clothing.

• Wash with soap and water before eating or smoking.

• See MSDS

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FUTURE DIESEL FUEL

• All changes driven by lower emissions.

• June 1, 2006: ULSD = 15 ppm sulphurfor on-road diesel fuel.

Harmonized with U.S.

• 2007?: off-road diesel fuel: 500 ppm S ?

• 2010?: possible limits on cetane / density / aromatics / < 10 ppm sulphur?

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QUESTIONS ??

• Are there any questions on fuel topics?

There are no silly questions…

There are only people who make

silly mistakes because they didn’t ask simple questions!

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HIGH QUALITY

DIESEL FUEL

Dr. Andy Pickard

Senior Advisor, Fuels

Petro-Canada

pickard@petro-canada.ca

(403) 296-8019

North American

Council of

Automotive Teachers

2001