Course SpecificationsCourse Specifications  

A Basic InformationA Basic Information    Course Title: Course Title: Heat Engine and Combustion (B) Heat Engine and Combustion (B)

Code:MPE321Code:MPE321 Lecture: 2Lecture: 2 Tutorial: 2Tutorial: 2 Practical: 0Practical: 0 Total: 4Total: 4 Program on which the course is given:Program on which the course is given: B.Sc. B.Sc.

Mechanical Engineering (Power)Mechanical Engineering (Power) Major or minor element of program:Major or minor element of program: MajorMajor Department offering the program: Mechanical Engineering Department offering the program: Mechanical Engineering

DepartmentDepartment Department offering the course: Mechanical Engineering Department offering the course: Mechanical Engineering

DepartmentDepartment Academic year / level: Third Year / Second Semester Academic year / level: Third Year / Second Semester Date of specifications approval: 10/5/2006Date of specifications approval: 10/5/2006

B- Professional InformationB- Professional Information

1- Overall aims of course1- Overall aims of course

By the end of the course the students will be able By the end of the course the students will be able to:to:

Identify the different types of fuels and their Identify the different types of fuels and their properties. properties.

- Understand the concepts and principles of the - Understand the concepts and principles of the chemical reactions. chemical reactions.

- Understand the basic principles of the chemical and - Understand the basic principles of the chemical and the phase equilibrium.the phase equilibrium.

- Apply the first and second law of thermodynamics on - Apply the first and second law of thermodynamics on chemical reactions.chemical reactions.- Know the different types of flames and their theories.- Know the different types of flames and their theories.

- Know the construction and operation of the industrial - Know the construction and operation of the industrial furnaces and their applications.furnaces and their applications.

- Know the factors affecting the furnaces performance. - Know the factors affecting the furnaces performance.

2-Intended Learning Outcomes (ILOs)2-Intended Learning Outcomes (ILOs)

a) a) Knowledge and Understanding:Knowledge and Understanding: a.5) Methodologies of solving engineering a.5) Methodologies of solving engineering

problems, data collection interpretation.problems, data collection interpretation. a.8) Current engineering technologies as related a.8) Current engineering technologies as related

to disciplines.to disciplines. a.13) Fundamentals of thermal and fluid a.13) Fundamentals of thermal and fluid

processes.processes. a.18) Mechanical power and energy engineering a.18) Mechanical power and energy engineering

contemporary issues.contemporary issues. a.19) Basic theories and principles of some other a.19) Basic theories and principles of some other

engineering and mechanical engineeringengineering and mechanical engineering disciplines providing support to mechanical disciplines providing support to mechanical power and energy disciplinespower and energy disciplines

2-Intended Learning Outcomes (ILOs)2-Intended Learning Outcomes (ILOs)b) Intellectual Skillsb) Intellectual Skills b.1) Select appropriate mathematical and b.1) Select appropriate mathematical and

computer-based methods for modeling and computer-based methods for modeling and analyzing problems.analyzing problems.

b.5) Assess and evaluate the characteristics and b.5) Assess and evaluate the characteristics and performance of components, systems and performance of components, systems and processesprocesses

b.7) Solve engineering problems, often on the b.7) Solve engineering problems, often on the basis of limited and possibly contradicting basis of limited and possibly contradicting information.information.

b.11) Analyze results of numerical models and b.11) Analyze results of numerical models and appreciate their limitations.appreciate their limitations.

b.13) Evaluate mechanical power and energy b.13) Evaluate mechanical power and energy engineering design, processes, and engineering design, processes, and performance and propose improvements. performance and propose improvements.

2-Intended Learning Outcomes (ILOs)2-Intended Learning Outcomes (ILOs)

Professional and Practical SkillsProfessional and Practical Skills c.1) Apply knowledge of mathematics, c.1) Apply knowledge of mathematics,

science, information technology, design, science, information technology, design, business context and engineering practice business context and engineering practice to solve engineering problems.to solve engineering problems.

c.12) Prepare and present technical reports.c.12) Prepare and present technical reports. c.16) Describe the basic thermal and fluid c.16) Describe the basic thermal and fluid

processes mathematically and use the processes mathematically and use the computer software for their simulation and computer software for their simulation and analysis.analysis.

1-Intended Learning Outcomes (ILOs)1-Intended Learning Outcomes (ILOs)

General and Transferable SkillsGeneral and Transferable Skills d.3) Communicate effectively.d.3) Communicate effectively. d.4) Demonstrate efficient IT capabilities. d.4) Demonstrate efficient IT capabilities. d.7) Search for information and engage in d.7) Search for information and engage in

life-long self learning discipline.life-long self learning discipline.   

3- Contents3- ContentsNo Topic No. of

hoursILOs Teaching / learning methods and

strategiesAssessment method

1 Fuel types and properties 2 a.8, c.12,d.4,d.7 Lecture Report

2Chemical reactionsTheoretical and actual combustion processes

2a.5, a.13, b.5, b.7, b.13, c.1

Lecture – tutorial Assignment

3Enthaply of formation, enthalpy of reaction

2a.5, a.13, b.5, b.7, b.13, c.1

Lecture – tutorial Assignment

41st and 2nd law analysis of combustion processes

2a.5, a.13, b.5, b.7, b.13, c.1

Lecture – tutorial Quiz

5 Chemical equilibrium 2 a.13,b.7, c.1 Lecture – tutorial Assignment

6Chemical equilibrium (continued)

2a.13,b.7, c.1 Lecture – tutorial Quiz

7 Phase equilibrium 2 a.13,b.7, c.1 Lecture – tutorial Assignment 8 Mid-term exam

9 Laminar premixed flames 2a.8,a.13,a.19,b.7, c.1,

c.12,c.16, d.3,d.7 Lecture – tutorial Assignment

10 Laminar diffusion flames 2a.8,a.13,a.19,b.7, c.1,

c.12,c.16, d.3,d.7 Lecture – tutorial Quiz - Report

11Turbulent premixed and non-premixed flames

2a.8,a.13,a.19,b.7, c.1,

c.12,c.16, d.3,d.7 Lecture – tutorial Assignment

12Introduction to industrial furnaces

2a.8,a.13,a.19,b.7, b.13,

c.1,c.12, d.4, d.7Lecture – tutorial Assignment

13Heat transfer in industrial furnaces

2a.8,a.13,a.19,b.7, b.13,

c.1,c.12, d.4, d.7Lecture – tutorial Quiz

14Saving energy in industrial furnacs

2a.8,a.13,a.19,b.7, b.13,

c.1,c.12, d.4, d.7Lecture – tutorial Assignment - Report

15 Final exam

Teaching and Learning MethodsTeaching and Learning Methods __√__ Lectures__√__ Lectures _____ Practical training / laboratory_____ Practical training / laboratory _____ Seminar / workshop_____ Seminar / workshop ____ Class activity____ Class activity __√__ Tutorial __√__ Tutorial _____ Case study_____ Case study __√__ Assignments / homework__√__ Assignments / homework Other : Other : Self studySelf study

Student Assessment MethodsStudent Assessment Methods ________ Assignments to assess ________ Assignments to assess knowledge and knowledge and

intellectual skillsintellectual skills. .. . ________ Quiz to assess ________ Quiz to assess knowledge, intellectual and knowledge, intellectual and

professional skills.professional skills. ________ Mid-term exam to assess ________ Mid-term exam to assess knowledge, intellectual, knowledge, intellectual,

professional and general skills.professional and general skills. ________ Oral exam to assess ________ Oral exam to assess knowledge, intellectual, knowledge, intellectual,

professional and general skills.professional and general skills. ________ Final exam to assess ________ Final exam to assess knowledge, intellectual, knowledge, intellectual,

professional and general skills.professional and general skills. Other: Other: Self study Self study to assess to assess knowledge, intellectual, knowledge, intellectual,

professional and general skillsprofessional and general skills..   

1.Assessment scheduleAssessment 1 on weeks 2, 5, 9, 11Assessment 2 Quizzes on weeks 4, 6, 10, 13Assessment 3 Mid-term exam on week 8Assessment 4 Oral Exam on week 14Assessment 5 Final exam on week 15

Weighting of AssessmentsMid- Term Examination 15%Final- Term Examination 60%Oral Examination 15%Practical Examination 00%Semester Work 05%Other 05% Total 100%

8- List of References8- List of References

8.1- G. Van Wylen, R. Sonntag and C. 8.1- G. Van Wylen, R. Sonntag and C. Borgnakke, "Fundamentals of Classical Borgnakke, "Fundamentals of Classical Thermodynamics", Jhon Wiley &Sons. Thermodynamics", Jhon Wiley &Sons. 1994.1994.

8.2-.Yunis, A. Cengle, and Michael A. 8.2-.Yunis, A. Cengle, and Michael A. Boles, “Thermodynamics- an Engineering Boles, “Thermodynamics- an Engineering Approach” Fifth edition, Approach” Fifth edition,

8.3-.J. Warnatz · U. Maas · R.W. Dibble, 8.3-.J. Warnatz · U. Maas · R.W. Dibble, “Combustion”, Springer-Verlag Berlin “Combustion”, Springer-Verlag Berlin Heidelberg 1996, 1999, 2001 Heidelberg 1996, 1999, 2001

Facilities Required for Teaching and learningFacilities Required for Teaching and learning Lecture room Lecture room Presentation board, computer and data showPresentation board, computer and data show    Course coordinator: Course coordinator: Prof. Dr.Prof. Dr. Ramadan Y. Sakr Ramadan Y. Sakr Course instructor: Course instructor: Prof. Dr. Prof. Dr. Ramadan Y. Sakr Ramadan Y. Sakr Head of department:Head of department: Prof. Dr.Prof. Dr. Maher G. A. Higazy Maher G. A. Higazy

Date: 26/10/ 2011Date: 26/10/ 2011

Fuels & Fuels Properties Fuels & Fuels Properties

Lecture 1Lecture 1

Crude OilCrude Oil

Found in rock formations that were Found in rock formations that were ocean floors.ocean floors.

Organic matter from seas became Organic matter from seas became trapped by sediments at ocean floor.trapped by sediments at ocean floor.

Progressing cracking of the Progressing cracking of the molecules and elimination of oxygen molecules and elimination of oxygen turned organic matter into turned organic matter into petroleum.petroleum.

Crude OilCrude Oil

Petroleum is made of 86% carbon Petroleum is made of 86% carbon and 14% hydrogen.and 14% hydrogen.

Hydrocarbon molecules are Hydrocarbon molecules are accompanied by dirt, water, sulfur accompanied by dirt, water, sulfur and other impurities.and other impurities.

Crude oil must be refined to produce Crude oil must be refined to produce suitable engine fuels. suitable engine fuels.

Fig. 5.1: Molecular Structures of Fig. 5.1: Molecular Structures of Some Hydrocarbon Fuel FamiliesSome Hydrocarbon Fuel Families

Fig. 5.2: Flow Diagram for Typical Fig. 5.2: Flow Diagram for Typical Petroleum RefineryPetroleum Refinery

Fig. 5.3: Distillation Curve for Fig. 5.3: Distillation Curve for Crude Oil.Crude Oil.

Distillation TemperaturesDistillation Temperatures

30 to 230 C for Gasoline30 to 230 C for Gasoline 230 to 370 C for Diesel230 to 370 C for Diesel Most refineries utilize “cracking units” Most refineries utilize “cracking units”

where catalysts at high temperatures where catalysts at high temperatures and pressures crack the larger and pressures crack the larger hydrocarbon molecules into smaller ones hydrocarbon molecules into smaller ones shifting production towards gasoline.shifting production towards gasoline.

Fractionating towers allow smaller Fractionating towers allow smaller molecules to condense out at cooler molecules to condense out at cooler temperatures in the upper portion of the temperatures in the upper portion of the tower. tower.

Ideal CombustionIdeal Combustion

All of the H in fuel is converted All of the H in fuel is converted to Hto H220.0.

All of the C in fuel is converted All of the C in fuel is converted to COto CO22..

Air is 21% O and 79% N by Air is 21% O and 79% N by volume.volume.

Combustion of GasolineCombustion of Gasoline

Stoichiometric Air/Fuel Mixture Stoichiometric Air/Fuel Mixture

For gasoline…For gasoline…

1:1.15

1

54.1151.3/

FA

Table 5.2: Representative Fuel Table 5.2: Representative Fuel MoleculesMolecules

Fig.1-1 Aliphatic hydrocarbons

Fig.1-2 Alicyclic and aromatic hydrocarbo

Fig. 1-3 Structural formulae for oxygenous hydrocarbons

Fig. (1-4) Boiling graph for gasoline and diesel fuel, as well as kerosene and water

Definition of the octane number (ON) for gasoline fuels

The octane number is defined as the isooctane fraction of the comparison fuel.

Definition of the cetane number (CN) for diesel fuels

In determining ignition performance, we use a comparison fuel, which is, in this case, a two component fuel composed of:

For the determination of ignition performance, we use a so-called comparison fuel, i.e. a two component fuel consisting of

A fuel can be considered as a finite resource of chemical

potential energy, i.e., energy stored in the molecular

structure of particular compounds that may be released

via complex chemical reactions.

Some of the basic ideal combustion engineering

characteristics of a fuel include:

High energy density (content)

High heat of combustion (release)

Good thermal stability (storage)

Low vapor pressure (volatility)

Nontoxicity (environmental impact)

THE FUEL-ENGINE INTERFACE

Gasoline Engine ExhaustGasoline Engine Exhaust

SI engines are often operated with SI engines are often operated with “rich” air/fuel mixtures to produce “rich” air/fuel mixtures to produce more power – inadequate oxygen more power – inadequate oxygen supply results in production of CO supply results in production of CO (not all carbon is converted to CO2).(not all carbon is converted to CO2).

Even with lean mixtures, CO is still Even with lean mixtures, CO is still produced. DO NOT OPERATE produced. DO NOT OPERATE GASOLINE ENGINES IN CONFINED GASOLINE ENGINES IN CONFINED SPACES!!! SPACES!!!

Diesel Air/Fuel RatiosDiesel Air/Fuel Ratios

Stoichiometric air/fuel mixture for CI Stoichiometric air/fuel mixture for CI engines 14.9:1.engines 14.9:1.

However, most CI engines are However, most CI engines are operated with a leaner air/fuel ration operated with a leaner air/fuel ration and therefore free oxygen is often and therefore free oxygen is often found in the exhaust. found in the exhaust.

Diesel Engine ExhaustDiesel Engine Exhaust

Small quantities of unburned fuel escape Small quantities of unburned fuel escape in gaseous form.in gaseous form.

At high temperatures N reacts with O to At high temperatures N reacts with O to form NO and NO2 (together these are form NO and NO2 (together these are known as NOx).known as NOx).

Federal government has established limits Federal government has established limits on CO, NOx and unburned hydrocarbon in on CO, NOx and unburned hydrocarbon in engine exhaust – Tier I through IV engine exhaust – Tier I through IV Regulations. Regulations.

Emission Regulations (EPA)Emission Regulations (EPA)

Example 5.1Example 5.1

What is the air/fuel ratio and the What is the air/fuel ratio and the exhaust products when ethanol is exhaust products when ethanol is used as an engine fuel? used as an engine fuel?

SolutionSolution

95.81/)866.6087.2(/

174.1913.1866.6866.6087.21

)18(3)44(2)28(28.11)28(28.11)32(3)46(1

3228.1128.113 2222262

FA

OHCONNOOHC

General Combustion EquationsGeneral Combustion Equations

Equations are cast in a form that includes Equations are cast in a form that includes a measure of “richness,”a measure of “richness,”

where f is the “richness” term.where f is the “richness” term.

actual

stoich

FA

FA

/

/

General Combustion EquationsGeneral Combustion Equations

The “General Combustion Equation” is,The “General Combustion Equation” is,

where x, y and z are the relative number of where x, y and z are the relative number of atoms of C, H and O, respectively; and U, R, atoms of C, H and O, respectively; and U, R, V and W are defined in the following V and W are defined in the following relationships.relationships.

OHy

OWCOVCORNU

NU

OU

OHC zyx 222222 276.376.3

General Combustion EquationsGeneral Combustion Equations

10

111

11

12

10

11

12

124

whenW

whenUW

whenUV

whenV

whenuxR

whenxR

zyxU

General Combustion EquationsGeneral Combustion Equations

The actual A/F ratio becomes,The actual A/F ratio becomes,

zyx

UFA actual 1612

3.137/

General Combustion EquationsGeneral Combustion Equations

WVRU

T

T

WCONC

T

VCONC

T

RCONC

T

UCONC

O

CO

CO

N

76.3

76.3

2

2

2

The theoretical dry exhaust gas The theoretical dry exhaust gas concentrations (volumetric basis) concentrations (volumetric basis) become,become,

Blended FuelsBlended Fuels

Blended fuels are common – for Blended fuels are common – for example blends of 10 % ethanol and example blends of 10 % ethanol and 90% gasoline are used to meet EPA 90% gasoline are used to meet EPA requirements for oxygenated fuels in requirements for oxygenated fuels in regions of the country with impaired regions of the country with impaired air quality.air quality.

Blended FuelsBlended Fuels

The composite fuel molecule can be The composite fuel molecule can be estimated using,estimated using,

where the “p” subscript denotes the where the “p” subscript denotes the primary fuel, and “s” the secondary; and primary fuel, and “s” the secondary; and variable f is the faction (decimal form) of variable f is the faction (decimal form) of either fuel.either fuel.

spp

psss mf

mfr

Blended FuelsBlended Fuels

The resulting composite fuel molecule The resulting composite fuel molecule becomes, becomes,

zpzsrzc

ypysryc

xpxsrxc

where

OHC

s

s

s

zcycxc

Octane RatingsOctane Ratings

Octane is a measure of gasoline’s Octane is a measure of gasoline’s resistance to “knock.”resistance to “knock.”

““Knock” is the uncontrolled release Knock” is the uncontrolled release of energy when combustion initiates of energy when combustion initiates somewhere other than the spark somewhere other than the spark plug.plug.

Symptoms of engine “knock” include Symptoms of engine “knock” include an audible “knocking” or “pining” an audible “knocking” or “pining” sound under acceleration. sound under acceleration.

Fig. 5.5: Knock in SI engines.Fig. 5.5: Knock in SI engines.

Causes of Engine KnockCauses of Engine Knock Knock is caused when the Knock is caused when the

temperature in the cylinder reaches temperature in the cylinder reaches the self ignition temperature (SIT) of the self ignition temperature (SIT) of the end gases.the end gases.

The end gases do not readily ignite, The end gases do not readily ignite, rather there is an ignition delay rather there is an ignition delay caused by pre-flame reactions.caused by pre-flame reactions.

Engine knock is more prevalent under Engine knock is more prevalent under conditions that include:conditions that include: Lean air/fuel ratiosLean air/fuel ratios High compression ratiosHigh compression ratios

Methods to Reduce Engine KnockMethods to Reduce Engine Knock

Use wedge shaped combustion Use wedge shaped combustion chambers to cool end gases more chambers to cool end gases more readily.readily.

Use gasoline with higher octane Use gasoline with higher octane ratings – these ratings are associated ratings – these ratings are associated with gasoline that has few straight with gasoline that has few straight chain carbons have longer ignition chain carbons have longer ignition delay times. delay times.

Octane Rating MeasurementOctane Rating Measurement

Procedure developed by the Procedure developed by the Cooperative Fuels Research Cooperative Fuels Research Committee (CFR).Committee (CFR).

The committee proposed a single The committee proposed a single cylinder SI engine to measure octane cylinder SI engine to measure octane – the CFR engine has an adjustable – the CFR engine has an adjustable compression ratio.compression ratio.

Engine is driven at a constant speed Engine is driven at a constant speed with an electric motor. with an electric motor.

Octane Rating MeasurementOctane Rating Measurement

Octane ratings are obtained by comparing Octane ratings are obtained by comparing fuel in question to iso-octane (Octane Rating fuel in question to iso-octane (Octane Rating of 100) and heptane (Octane Rating of 100).of 100) and heptane (Octane Rating of 100).

CR is adjusted until “knocking” is detected CR is adjusted until “knocking” is detected with fuel being tested.with fuel being tested.

Blends of iso-octane and heptane are tested Blends of iso-octane and heptane are tested until the same level of knock is obtained.until the same level of knock is obtained.

Octane rating is % of iso-octane in test blend. Octane rating is % of iso-octane in test blend.

Fig. 5.6: CFR EngineFig. 5.6: CFR Engine

Octane RatingsOctane Ratings CFR developed initial method (Motor CFR developed initial method (Motor

Octane Number – MON).Octane Number – MON). ASTM developed a new method (Research ASTM developed a new method (Research

Octane Number – RON).Octane Number – RON). RON octane ratings are 8 points low than RON octane ratings are 8 points low than

MON for most gasoline.MON for most gasoline. Most retailers report the Anti-Knock Index Most retailers report the Anti-Knock Index

which is an average of MON and RON.which is an average of MON and RON. Octane ratings of fuel are adjusted for Octane ratings of fuel are adjusted for

elevation – lower atmospheric pressure elevation – lower atmospheric pressure reduces the tendency for engine knock to reduces the tendency for engine knock to occur. occur.

Cetane Ratings and CI EnginesCetane Ratings and CI Engines

Octane rating is not a good way to Octane rating is not a good way to predict “knock” in CI engines.predict “knock” in CI engines.

Combustion in diesel engines consists Combustion in diesel engines consists of a two part delay – physical and of a two part delay – physical and chemical.chemical.

Physical - the fuel is injected and Physical - the fuel is injected and atomized.atomized.

Chemical - process proceeds with a Chemical - process proceeds with a pre-flame chemical reaction, similar to pre-flame chemical reaction, similar to that of SI engines. that of SI engines.

Fig. 5.7: Critical Compression Fig. 5.7: Critical Compression Ratios and TemperaturesRatios and Temperatures

Combustion ProcessCombustion Process

Pre-Mix Combustion – prepared mixture Pre-Mix Combustion – prepared mixture burns rapidly after compression ignition.burns rapidly after compression ignition.

Diffusion Combustion – fuel vapor Diffusion Combustion – fuel vapor diffuses into burn-out zones from one diffuses into burn-out zones from one side while oxygen diffuses from the side while oxygen diffuses from the other sustaining the combustion other sustaining the combustion process.process.

Diffusion process is much slower than Diffusion process is much slower than the pre-mix. Pre-mix generate the pre-mix. Pre-mix generate characteristic diesel rattle.characteristic diesel rattle.

Fig. 5.8: Energy release from Fig. 5.8: Energy release from CI fuels.CI fuels.

Altering Knock in CI EnginesAltering Knock in CI Engines

Ignition delay controls the relative Ignition delay controls the relative release of energy between the two release of energy between the two phases of combustion – a longer phases of combustion – a longer delay results in more energy delay results in more energy produces in the pre-mix phase.produces in the pre-mix phase.

Since “knock” occurs when more Since “knock” occurs when more energy is released at the start of energy is released at the start of combustion, it follows that “knock” is combustion, it follows that “knock” is reduced with short delay periods. reduced with short delay periods.

Cetane RatingsCetane Ratings

Cetane rating are an indication of the Cetane rating are an indication of the fuel’s anti-knock resistance for CI fuel’s anti-knock resistance for CI engines.engines.

Fuels with high cetane ratings are Fuels with high cetane ratings are created by increasing the proportion created by increasing the proportion of long chain molecules, thereby of long chain molecules, thereby reducing the ignition delay.reducing the ignition delay.

Fuels with high Octane Rating have Fuels with high Octane Rating have low cetane ratings!low cetane ratings!

Cetane RatingsCetane Ratings

CFR cetane rating process is similar CFR cetane rating process is similar to the Octane process with a couple to the Octane process with a couple of differences:of differences: Cetane and hyptamethylnonane are the Cetane and hyptamethylnonane are the

reference fuels.reference fuels. Hyptamethylnonane has a cetane rating Hyptamethylnonane has a cetane rating

of 15.of 15.

Effect of Cetane RatingEffect of Cetane Rating If cetane rating is too low, the ignition delay If cetane rating is too low, the ignition delay

results in hard starting (combustion after piston is results in hard starting (combustion after piston is moving downward) and characteristic ”white moving downward) and characteristic ”white smoke.”smoke.”

High cetane ratings start the combustion process High cetane ratings start the combustion process to soon, and some the fuel is not volatized and to soon, and some the fuel is not volatized and does not burn.does not burn.

““Black smoke” in heavily loaded engines is a Black smoke” in heavily loaded engines is a symptom of high cetane ratings.symptom of high cetane ratings.

Minimum cetane rating for CI engines is 40 Minimum cetane rating for CI engines is 40 according to SAE.according to SAE.

Commercial fuels seldom exceed 50.Commercial fuels seldom exceed 50. Cetane rating should never exceed 60. Cetane rating should never exceed 60.

Table 5: limiting values for Table 5: limiting values for diesel fuels.diesel fuels.

Fuel PropertiesFuel Properties

Standards OrganizationsStandards Organizations SAE – Society of Automotive EngineersSAE – Society of Automotive Engineers ASTM – American Society for the Testing ASTM – American Society for the Testing

of Materialsof Materials API – American Petroleum InstituteAPI – American Petroleum Institute

Specific GravitySpecific Gravity

A measure of the density of liquid fuels at A measure of the density of liquid fuels at 15.6 C as compared with water at the same 15.6 C as compared with water at the same temperature.temperature.

API devised the following scale,API devised the following scale,

where SG is the specific gravity.where SG is the specific gravity. A hydrometer, calibrated in APIo, is used to A hydrometer, calibrated in APIo, is used to

measure the specific gravity. measure the specific gravity.

5.1315.141

SGAPI o

Fig. 5.9: Fuel hydrometer.Fig. 5.9: Fuel hydrometer.

Heating Value of FuelHeating Value of Fuel

Determined using bomb calorimeter.Determined using bomb calorimeter. Bomb calorimeter measures “low Bomb calorimeter measures “low

heating value” – void of energy heating value” – void of energy required to evaporate water.required to evaporate water.

““High heating value” is found by High heating value” is found by adding the latent heat of adding the latent heat of vaporization of water to “low heating vaporization of water to “low heating value.” value.”

Table 5.4: Properties of Table 5.4: Properties of selected fuels.selected fuels.

Heating Value Estimates for Heating Value Estimates for Petroleum FuelsPetroleum Fuels

Heating values are estimated from Heating values are estimated from the API gravity,the API gravity,

where Hg is the gross (high) heating where Hg is the gross (high) heating value and Hn is the net (low) heating value and Hn is the net (low) heating value.value.

)/(000,107190.0

)/(1093860,42

kgkJHH

kgkJAPIH

gn

g

Fuel VolatilityFuel Volatility

Volatility refers to the ability of the fuel Volatility refers to the ability of the fuel to vaporize at lower temperatures.to vaporize at lower temperatures.

Reid vapor pressure and distillation Reid vapor pressure and distillation curves are indicators of fuel volatility.curves are indicators of fuel volatility.

Reid vapor pressure (RVP) is a Reid vapor pressure (RVP) is a standardized test using bomb standardized test using bomb calorimeter at 37.1 C – pressure is calorimeter at 37.1 C – pressure is measured using a suitable gage. measured using a suitable gage.

Fuel VolatilityFuel Volatility

Prior to 1990 winter gasoline Prior to 1990 winter gasoline volatility ranged from 60 to 80 kPa.volatility ranged from 60 to 80 kPa.

Summer gasoline was 10 to 15 kPa Summer gasoline was 10 to 15 kPa lower to reduce the potential for lower to reduce the potential for vaporization.vaporization.

Clean Air Act (1990) limits maximum Clean Air Act (1990) limits maximum vapor pressures to 56 kPa in the vapor pressures to 56 kPa in the large Northern U.S. cities and 49 kPa large Northern U.S. cities and 49 kPa in large Southern U.S. cities. in large Southern U.S. cities.

Distillation TestsDistillation Tests

100 ml sample is distilled.100 ml sample is distilled. Fuel temperature is recorded for first Fuel temperature is recorded for first

condensed drop (boiling point), and condensed drop (boiling point), and then at 10 ml intervals during the then at 10 ml intervals during the distillation process.distillation process.

T10, T50 and T90 temperatures are T10, T50 and T90 temperatures are important to engine characteristics important to engine characteristics which include easy of starting, warm-which include easy of starting, warm-up, and crankcase dilution and fuel up, and crankcase dilution and fuel economy, respectively. economy, respectively.

Fig. 5.10: Fuel distillation Fig. 5.10: Fuel distillation aparataus.aparataus.

Adjusting Distillation Temperatures Adjusting Distillation Temperatures

Gasoline sold during the winter must Gasoline sold during the winter must be more volatile for easy starting in be more volatile for easy starting in the winter.the winter.

Gasoline sold for use in high Gasoline sold for use in high elevations must be less volatile to elevations must be less volatile to avoid “vapor lock” in the summer.avoid “vapor lock” in the summer.

Volatility is adjusted by adding Volatility is adjusted by adding butane and lighter hydrocarbons. butane and lighter hydrocarbons.

Adjusting Distillation Temperatures Adjusting Distillation Temperatures

For diesel engines:For diesel engines: Low T10 values aids cold weather Low T10 values aids cold weather

starting.starting. Low T50 values minimize smoke and Low T50 values minimize smoke and

odor.odor. Low T90 values reduce crankcase Low T90 values reduce crankcase

dilution and improve fuel economy.dilution and improve fuel economy.

Fig. 5.11: Distillation curves.Fig. 5.11: Distillation curves.

Fuel ViscosityFuel Viscosity

Viscosity is a measure of the flow Viscosity is a measure of the flow resistance of liquid.resistance of liquid.

Fuel viscosity must be high enough Fuel viscosity must be high enough to insure good lubrication of injection to insure good lubrication of injection pump mechanisms in CI engines.pump mechanisms in CI engines.

Fuel viscosity must be low enough to Fuel viscosity must be low enough to insure proper atomization at the time insure proper atomization at the time of injection. of injection.

Cloud and Pour PointsCloud and Pour Points

Cloud point is the temperature at Cloud point is the temperature at which crystals begin to form in the which crystals begin to form in the fuel.fuel.

Pour point is the temperature at which Pour point is the temperature at which the fuel ceases to flow.the fuel ceases to flow.

Cloud point are typically 5 to 8 C Cloud point are typically 5 to 8 C higher than pour point,higher than pour point,

Not an issue for gasoline.Not an issue for gasoline. Values are important for diesel.Values are important for diesel.

Fuel Impurities - SulfurFuel Impurities - Sulfur

Sulfur oxides – can convert to acids Sulfur oxides – can convert to acids which corrode engine parts and which corrode engine parts and cause increased wear.cause increased wear.

Assessed by immersing copper strip Assessed by immersing copper strip in fuel for three hours, then in fuel for three hours, then comparing corrosion to standard comparing corrosion to standard strips.strips.

Fuel Impurities - AshFuel Impurities - Ash

Ash – small solid particles or water-Ash – small solid particles or water-soluble metals found fuels.soluble metals found fuels.

Defined as un-burned fuel residue Defined as un-burned fuel residue left behind.left behind.

Can cause accelerated wear of close-Can cause accelerated wear of close-fitting injection system parts.fitting injection system parts.

Fuel Impurities – Water and Fuel Impurities – Water and SedimentSediment

Moisture can condense in fuel Moisture can condense in fuel storage tanks, or seep in from storage tanks, or seep in from underground leaks.underground leaks.

Fuel should be bright and clear, and Fuel should be bright and clear, and visibly free of water and sediment.visibly free of water and sediment.

Fuel Impurities - GumFuel Impurities - Gum

Gum can form in gasoline, leaves Gum can form in gasoline, leaves behind deposits on carburetors. behind deposits on carburetors. Gum is dissolved by gasoline – more Gum is dissolved by gasoline – more prevalent in gasoline that is made by prevalent in gasoline that is made by cracking.cracking.

Antioxidants are now added to both Antioxidants are now added to both diesel and gasoline to extend storage diesel and gasoline to extend storage life without gum formation.life without gum formation.

Fuel AdditivesFuel Additives

Until 1970, gasoline contained TEL Until 1970, gasoline contained TEL (tetraethyl lead). TEL was used as (tetraethyl lead). TEL was used as an octane booster.an octane booster.

MTBE (methyl tertiary butyl ether) is MTBE (methyl tertiary butyl ether) is often substituted as an octane often substituted as an octane booster – could be phased booster – could be phased out/banned by EPA soon.out/banned by EPA soon.

Table 5.5: Gasoline additivesTable 5.5: Gasoline additives

Fuel StorageFuel Storage

Fuels classified according to Fuels classified according to flammability – gasoline is more flammability – gasoline is more dangerous with a flash point of -40 C.dangerous with a flash point of -40 C.

Major concern with regard to Major concern with regard to environmental contaminationenvironmental contamination

Fig. 5.12: Lubricating TheoryFig. 5.12: Lubricating Theory

nf FfF

Fig. 5.13: Action of Journal Fig. 5.13: Action of Journal BearingsBearings

a) at rest, b) in mixed-film lubrication, and c) in hydrodynamic lubrication

Fig. 5.14: Newtonian ViscosityFig. 5.14: Newtonian Viscosity

h

vAF

Fig. 5.15: Cannon-Fenske Fig. 5.15: Cannon-Fenske ViscometerViscometer

Reporting of ViscosityReporting of Viscosity

Kinematic viscosity (Kinematic viscosity () is reported as,) is reported as,

where m is absolute (or dynamic) where m is absolute (or dynamic) viscosity, and r is the fluid mass viscosity, and r is the fluid mass density.density.

Typical UnitsTypical Units

Centipoise (cP) was the popular unit of Centipoise (cP) was the popular unit of dynamic viscosity.dynamic viscosity.

Centistoke (cSt) was the popular unit of Centistoke (cSt) was the popular unit of kinematic viscosity.kinematic viscosity.

smPacP 11

smmcSt /11 2

Table 5.6: SAE Motor Oil Table 5.6: SAE Motor Oil ClassificationClassification

Motor Oil Service RatingsMotor Oil Service Ratings ““S”- SERVICE CLASSIFICATIONS FOR GASOLINE ENGINES  S”- SERVICE CLASSIFICATIONS FOR GASOLINE ENGINES  

SH- For 1994 Gasoline Engine Service SH- For 1994 Gasoline Engine Service -- Classification SH was adopted in -- Classification SH was adopted in 1992 and recommended for gasoline engines in passenger cars and light 1992 and recommended for gasoline engines in passenger cars and light trucks starting in 1993 model year. This category supercedes the trucks starting in 1993 model year. This category supercedes the performance requirements of API SG specification for 1989-1992 models, performance requirements of API SG specification for 1989-1992 models, which is now obsolete. Applications that call for an API service which is now obsolete. Applications that call for an API service classification SG can use the SH specification.  The specification classification SG can use the SH specification.  The specification addresses issues with deposit control, oxidation, corrosion, rust and wear addresses issues with deposit control, oxidation, corrosion, rust and wear and replaces.and replaces.

SJ- For 1997 Gasoline Engine ServiceSJ- For 1997 Gasoline Engine Service -- Classification SJ was adopted in -- Classification SJ was adopted in 1996 and recommended for gasoline engines in passenger cars and light 1996 and recommended for gasoline engines in passenger cars and light trucks starting in 1997 model year. Applications specifying API SH can trucks starting in 1997 model year. Applications specifying API SH can use the newer API SJ service classification.  Note that where applicable use the newer API SJ service classification.  Note that where applicable certain letters in the sequence will be skipped to prevent confusion with certain letters in the sequence will be skipped to prevent confusion with other standards. In this case, SI was skipped since industrial oils are other standards. In this case, SI was skipped since industrial oils are currently rated according to SI classifications. currently rated according to SI classifications. 

SL- For 2001 and Newer Gasoline Engine Service- Current Spec.SL- For 2001 and Newer Gasoline Engine Service- Current Spec. -- -- Recommended for gasoline engines in passenger cars and light trucks Recommended for gasoline engines in passenger cars and light trucks starting in July 2001. SL oils are engineered to provide improved high starting in July 2001. SL oils are engineered to provide improved high temperature deposit control and lower oil consumption. Applications temperature deposit control and lower oil consumption. Applications specifying API SJ can use the new API SL service classification. Note that specifying API SJ can use the new API SL service classification. Note that some SL rated oils may also meet the latest ILSAC specification and/or some SL rated oils may also meet the latest ILSAC specification and/or qualify as energy conserving. SL is the latest specification.qualify as energy conserving. SL is the latest specification.

Motor Oil Service RatingsMotor Oil Service Ratings ““C”- COMMERCIAL CLASSIFICATIONS FOR DIESEL ENGINES C”- COMMERCIAL CLASSIFICATIONS FOR DIESEL ENGINES

CF-For 1994 Off-Road Indirect Injected Diesel Engine ServiceCF-For 1994 Off-Road Indirect Injected Diesel Engine Service --  -- API Service API Service Category CF denotes service typical of off-road, indirect injected diesel engines and Category CF denotes service typical of off-road, indirect injected diesel engines and other diesel engines that use a broad range of fuel types, including those using fuel other diesel engines that use a broad range of fuel types, including those using fuel with higher sulfur content (over 0.5% wt sulfur fuel).  Effective control of piston with higher sulfur content (over 0.5% wt sulfur fuel).  Effective control of piston deposits, wear and corrosion of copper-containing bearings is essential for these deposits, wear and corrosion of copper-containing bearings is essential for these engines, which may be naturally aspirated, turbocharged or supercharged.  Oils engines, which may be naturally aspirated, turbocharged or supercharged.  Oils designated for this service may also be used when API Service Category CD or CE is designated for this service may also be used when API Service Category CD or CE is recommended. CF is a current specification. recommended. CF is a current specification. 

CF-2- FOR 1994 Severe Duty 2-Stroke Cycle Diesel Engine ServiceCF-2- FOR 1994 Severe Duty 2-Stroke Cycle Diesel Engine Service -- API Service -- API Service Category CF-2 denotes service typical of two-stroke cycle engines (such as Detroit Category CF-2 denotes service typical of two-stroke cycle engines (such as Detroit Diesel) requiring highly effective control over cylinder and ring-face scuffing and Diesel) requiring highly effective control over cylinder and ring-face scuffing and deposits.  Oils designated for this service have been in existence since 1994 and deposits.  Oils designated for this service have been in existence since 1994 and may also be used when API Service Category CD-II is recommended.  These oils do may also be used when API Service Category CD-II is recommended.  These oils do not necessarily meet the requirements of CF or CF-4, unless they pass the test and not necessarily meet the requirements of CF or CF-4, unless they pass the test and performance requirements for these categories. CF-2 is a current specification.performance requirements for these categories. CF-2 is a current specification.

CF-4- For 1990 Diesel Engine ServiceCF-4- For 1990 Diesel Engine Service -- Service typical of severe duty  -- Service typical of severe duty turbocharged, 4-stroke cycle diesel engines, particularly late models designed to turbocharged, 4-stroke cycle diesel engines, particularly late models designed to give lower emissions.  These engines are usually found in on-highway, heavy-duty give lower emissions.  These engines are usually found in on-highway, heavy-duty truck applications.  API CF-4 oils exceed the requirement of CE category oils and truck applications.  API CF-4 oils exceed the requirement of CE category oils and can be used in place of earlier CC, CD and CE oils. CF-4 oils provide for improved can be used in place of earlier CC, CD and CE oils. CF-4 oils provide for improved control of piston deposits and oil consumption. The CF-4 classification meets control of piston deposits and oil consumption. The CF-4 classification meets Caterpillar’s 1k engine requirements, as well as earlier Mack Trucks (T-6 & T-7) and Caterpillar’s 1k engine requirements, as well as earlier Mack Trucks (T-6 & T-7) and Cummins (NTC-400) multi-cylinder engine test criteria. When combined with the Cummins (NTC-400) multi-cylinder engine test criteria. When combined with the appropriate “S” category, they can be used in gasoline and diesel powered cars appropriate “S” category, they can be used in gasoline and diesel powered cars and light trucks as specified by the vehicle and/or engine manufacturer. and light trucks as specified by the vehicle and/or engine manufacturer. 

Motor Oil Service RatingsMotor Oil Service Ratings CG-4- For 1995 Severe Duty Diesel Engine Service  -- CG-4- For 1995 Severe Duty Diesel Engine Service  -- API Service Category CG-4 API Service Category CG-4

describes oils for use in high speed, four-stroke cycle diesel engines used in describes oils for use in high speed, four-stroke cycle diesel engines used in highway and off-road applications, where the fuel sulfur content may vary from less highway and off-road applications, where the fuel sulfur content may vary from less than 0.05% by weight to less than 0.5% by weight.  CG-4 oils provide effective than 0.05% by weight to less than 0.5% by weight.  CG-4 oils provide effective control over high temperature piston deposits, wear, corrosion, foaming, oxidation control over high temperature piston deposits, wear, corrosion, foaming, oxidation stability and soot accumulation.  These oils are especially effective in engines stability and soot accumulation.  These oils are especially effective in engines designed to meet 1994 exhaust emissions standards and may also be used in designed to meet 1994 exhaust emissions standards and may also be used in engines requiring API Service Categories CD, CE and CF-4.  Oils designated for this engines requiring API Service Categories CD, CE and CF-4.  Oils designated for this service have been in existence since 1995. CG-4 is a current specification service have been in existence since 1995. CG-4 is a current specification 

CH-4- For 1999 Severe Duty Diesel Engine Service -- CH-4- For 1999 Severe Duty Diesel Engine Service -- API Service Category CH-4 API Service Category CH-4 describes oils for use in high speed, four-stroke cycle diesel engines used in describes oils for use in high speed, four-stroke cycle diesel engines used in highway and off-road applications.  CH-4 oils provide effective control over engine highway and off-road applications.  CH-4 oils provide effective control over engine deposits, wear, corrosion, oxidation stability and soot accumulation.  These oils are deposits, wear, corrosion, oxidation stability and soot accumulation.  These oils are especially effective in engines designed to meet 1999 emission standards and may especially effective in engines designed to meet 1999 emission standards and may also be used in engines requiring API Service Category CG-4.  Oils designated for also be used in engines requiring API Service Category CG-4.  Oils designated for this service have been in existence since 1999. CH-4 oils are engineered for use this service have been in existence since 1999. CH-4 oils are engineered for use with diesel fuels ranging in sulfur content up to 0.5% weight.  CH-4 is a current with diesel fuels ranging in sulfur content up to 0.5% weight.  CH-4 is a current specification. specification. 

CL-4- For 2002 Severe Duty Diesel Engine ServiceCL-4- For 2002 Severe Duty Diesel Engine Service -- API Service Category CL-4  -- API Service Category CL-4 describes oils for use in those high speed, four-stroke cycle diesel engines designed describes oils for use in those high speed, four-stroke cycle diesel engines designed to meet 2004 exhaust emissions standards and was implemented in October 2002.  to meet 2004 exhaust emissions standards and was implemented in October 2002.  These oils are engineered for all applications where diesel fuel sulfur content is up These oils are engineered for all applications where diesel fuel sulfur content is up to 0.05% by weight.  These oils are very effective at sustaining engine durability to 0.05% by weight.  These oils are very effective at sustaining engine durability where EGR ( Exhaust Gas Recirculation) and other exhaust emissions systems are where EGR ( Exhaust Gas Recirculation) and other exhaust emissions systems are used and provide for optimum protection in the areas of corrosive wear, low and used and provide for optimum protection in the areas of corrosive wear, low and high temperature stability, soot handling properties, piston deposit control, high temperature stability, soot handling properties, piston deposit control, valvetrain wear, oxidative thickening and foaming and viscosity loss due to shear.  valvetrain wear, oxidative thickening and foaming and viscosity loss due to shear.  API CL-4 oils are superior in performance to those meeting API-CH-4, CG-4 and CF-4 API CL-4 oils are superior in performance to those meeting API-CH-4, CG-4 and CF-4 and can be used and will effectively lubricate diesel engines specifying those API and can be used and will effectively lubricate diesel engines specifying those API service Classifications.service Classifications.

Table 5.8: Lubricating Oil AdditivesTable 5.8: Lubricating Oil Additives

Fig. 5.16: Pressure-Feed and Fig. 5.16: Pressure-Feed and Splash Lubrication System.Splash Lubrication System.