© Goodheart-Willcox Co., Inc. by Russell Krick Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois

© Goodheart-Willcox Co., Inc.

 Petroleum (crude oil)  Gasoline  Diesel fuel  Alternative fuels

© Goodheart-Willcox Co., Inc.  Oil taken directly from the ground  Used to make gasoline, diesel fuel, liquefied petroleum gas, and other petroleum products

© Goodheart-Willcox Co., Inc. Petroleum Products

© Goodheart-Willcox Co., Inc. Natural Crude Oil  Mixture of semisolids, liquids, and gases  Consists of highly flammable hydrocarbons  12% hydrogen  82% carbon

© Goodheart-Willcox Co., Inc. Processing Crude Oil To find oil, drill crews bore holes thousands of feet through dirt, sand, and rock using a cutting bit

© Goodheart-Willcox Co., Inc. Refinery  Converts crude oil into more useful substances  Distillation is the process used  during distillation, a fractionating tower is used to break the crude oil down into different parts, or fractions

© Goodheart-Willcox Co., Inc. Fractionating Tower Crude oil vapors condense and separate into trays

© Goodheart-Willcox Co., Inc.  The most common type of automotive fuel  An abundant and highly flammable part of crude oil

© Goodheart-Willcox Co., Inc. Gasoline Octane Rating  Measurement of the fuel’s ability to resist ignition caused by pressure and heat  resists knock or ping  Octane numbers give the antiknock value of gasoline

© Goodheart-Willcox Co., Inc. Gasoline Octane Rating

© Goodheart-Willcox Co., Inc. Octane Requirements  Octane requirements for an engine are published in the owner’s manual  Use a fuel with an octane number as high as or higher than the specifications  Engines with high compression or turbocharging often require higher octane fuels

© Goodheart-Willcox Co., Inc. Gasoline Additives  In the past, tetraethyl lead was used to increase octane rating  Oxygenates are now used to enhance octane rating  alcohols  toluene  ethanol  MTBE

© Goodheart-Willcox Co., Inc. Gasoline Combustion  For gasoline to burn properly, it must be mixed with the right amount of air  Mixture is compressed and ignited  Combustion produces heat  Heat causes gases to expand  Expansion causes pressure  Pressure pushes the piston down on the power stroke

© Goodheart-Willcox Co., Inc. Gasoline Combustion

© Goodheart-Willcox Co., Inc. Normal Gasoline Combustion  Occurs when the spark plug ignites the fuel and burning progresses smoothly through the fuel mixture  Requires about 3/1000 of a second  Maximum cylinder pressure should be produced a few degrees after Top Dead Center on the power stroke

© Goodheart-Willcox Co., Inc. Normal Gasoline Combustion

© Goodheart-Willcox Co., Inc. Normal Gasoline Combustion

© Goodheart-Willcox Co., Inc. Normal Gasoline Combustion

© Goodheart-Willcox Co., Inc. Normal Gasoline Combustion

© Goodheart-Willcox Co., Inc. Air-Fuel Mixture  For proper combustion and engine performance, the correct amounts of air and fuel must be mixed  Stoichiometric fuel mixture is a chemically correct air-fuel mixture  For gasoline, it is 14.7:1  14.7 parts of air to 1 part fuel, by weight  Under constant operating conditions, this mixture burns all of the fuel

© Goodheart-Willcox Co., Inc. Lean Air-fuel Mixture  Contains a large amount of air compared to fuel  Desirable for high fuel economy and low exhaust emissions  Too lean a mixture can cause poor performance  lack of power, misfire, or engine damage

© Goodheart-Willcox Co., Inc. Rich Air-fuel Mixture  Contains a larger amount of fuel mixed with the air  Increases engine power  Increases fuel consumption and exhaust emissions  An over-rich mixture will reduce power, foul spark plugs, and cause incomplete burning

© Goodheart-Willcox Co., Inc. Lean and Rich Air-Fuel Mixture

© Goodheart-Willcox Co., Inc. Abnormal Combustion  Occurs when the flame does not spread evenly and smoothly through the combustion chamber  Common types of abnormal combustion:  detonation  preignition  dieseling  spark knock

© Goodheart-Willcox Co., Inc. Detonation  Results when part of the unburned air- fuel mixture explodes violently  Severe and damaging type of abnormal combustion  Causes engine knock as the combustion chamber pressure rises so quickly that parts of the engine vibrate

© Goodheart-Willcox Co., Inc. Detonation

© Goodheart-Willcox Co., Inc. Detonation

© Goodheart-Willcox Co., Inc. Detonation

© Goodheart-Willcox Co., Inc. Detonation

© Goodheart-Willcox Co., Inc. Detonation Damage Detonation can shatter the insulator on a spark plug

© Goodheart-Willcox Co., Inc. Detonation Damage Detonation can blow a hole in a piston head

© Goodheart-Willcox Co., Inc. Preignition  Results when an overheated surface in the combustion chamber ignites the air- fuel mixture  “Hot spot” causes the mixture to burn prematurely  carbon particle, sharp metal edge, or hot exhaust valve  “Ping” can be heard during preignition

© Goodheart-Willcox Co., Inc. Preignition

© Goodheart-Willcox Co., Inc. Dieseling  Engine keeps running after the ignition is turned off  Knocking, coughing, or fluttering noise is heard as the fuel ignites and the crankshaft turns  Gasoline is ignited by heat and pressure in the cylinder

© Goodheart-Willcox Co., Inc. Dieseling  Common problem on carbureted engines  Common causes of dieseling:  high idle speed  carbon deposits in the combustion chambers  low-octane fuel  overheated engine  spark plug heat range too hot

© Goodheart-Willcox Co., Inc. Spark Knock  Occurs when the spark plug fires too soon in relation to the position of the piston  Caused by spark timing that is too advanced  Maximum cylinder pressure occurs too early, when the piston is still moving upward in the cylinder

© Goodheart-Willcox Co., Inc. Spark Knock

© Goodheart-Willcox Co., Inc. Spark Knock  Spark knock causes pinging under load  To find the cause, check the ignition timing first  If timing is correct, look for causes of preignition

© Goodheart-Willcox Co., Inc.  Diesel fuel contains more heat energy than gasoline by volume  Diesel fuel is a thicker fraction of crude oil

© Goodheart-Willcox Co., Inc. Diesel Fuel Injection  Diesel fuel will not vaporize as easily as gasoline  High-pressure injection is used to spray the fuel directly into the combustion chambers  High compression pressure heats the air in the cylinder  Fuel is vaporized and ignited by the hot air in the cylinder

© Goodheart-Willcox Co., Inc. Diesel Fuel Injection Diesel combustion chamber

© Goodheart-Willcox Co., Inc. Diesel Fuel Grades  Ensure that diesel fuel has uniform standards  There are three diesel fuel grades:  No. 1  No. 2  No. 4 (not used in highway vehicles)

© Goodheart-Willcox Co., Inc. Diesel Fuel Grades  No. 1  thinnest grade  may not provide adequate lubrication for injection system components on some engines  may be used as a winter fuel  No. 2  most commonly used in highway vehicles  used with additives for winter fuel

© Goodheart-Willcox Co., Inc. Cloud Point  Diesel fuel contains paraffin (wax)  At very cold temperatures, this wax can separate  Cloud point is the temperature at which paraffin separates out of the fuel  Paraffin can clog the fuel filters and prevent diesel engine operation

© Goodheart-Willcox Co., Inc. Water Contamination  When mixed with diesel fuel, water can clog filters and corrode components  Injection pumps and nozzles are very precise and easily damaged by water  Most diesel injection systems have water separators to prevent water damage

© Goodheart-Willcox Co., Inc. Cetane Rating  Indicates the cold starting ability of diesel fuel  Most automakers recommend a cetane rating of about 45  average rating of No. 2 diesel fuel  High cetane rating means the fuel will ignite easily from heat and pressure and burn quickly

© Goodheart-Willcox Co., Inc. Cetane Rating

© Goodheart-Willcox Co., Inc. Diesel Combustion  Diesel fuel requires compression- ignition  Fuel is injected directly into the combustion chamber  High compression heats the air  When fuel is sprayed into the hot air, it begins to burn

© Goodheart-Willcox Co., Inc. Diesel Combustion  Fuel is injected for several degrees of crankshaft rotation at TDC  This causes a smooth, steady buildup of pressure for quiet diesel engine operation

© Goodheart-Willcox Co., Inc. Normal Diesel Combustion

© Goodheart-Willcox Co., Inc. Diesel Knock  Occurs when too much fuel ignites at one time, producing a loud knock  Excessive diesel knock can reduce power, fuel economy, and engine life

© Goodheart-Willcox Co., Inc. Diesel Knock

© Goodheart-Willcox Co., Inc. Ignition Lag  Time required for diesel fuel to heat up, vaporize, and begin to burn  Time lapse between initial fuel injection and actual ignition  If lag time is too long, a large amount of fuel can ignite, producing a knock  High cetane fuel reduces the chances of diesel knock

© Goodheart-Willcox Co., Inc. Causes of Diesel Knock  Diesel knock has several causes:  cold engine operation  low-cetane fuel  improper fuel injector spray pattern  incorrect injection timing

© Goodheart-Willcox Co., Inc.  Any fuel other than gasoline and diesel fuel  Examples of alternative fuels:  liquefied petroleum gas (LPG)  alcohol  hydrogen

© Goodheart-Willcox Co., Inc. Liquefied Petroleum Gas  One of the lightest fractions of crude oil  Chemically similar to gasoline  Used in industrial equipment and fleet vehicles  Burns cleanly, producing low emissions  At room temperature and pressure, LPG is a vapor  LPG must be stored under pressure

© Goodheart-Willcox Co., Inc. LPG Fuel System

© Goodheart-Willcox Co., Inc. Alcohol  There are two types of alcohol used:  Ethyl alcohol (ethanol)  made from wheat, sugarcane, potatoes, fruit, oats, soy beans, or corn  Methyl alcohol (methanol)  made out of wood chips, petroleum, garbage, or animal manure

© Goodheart-Willcox Co., Inc. Alcohol  Clean-burning fuel for automobiles  Fuel system modifications are required to use alcohol  alcohol can be corrosive, requiring special materials  almost twice as much alcohol must be burned, compared to gasoline

© Goodheart-Willcox Co., Inc. Gasohol  Mixture of gasoline and alcohol  Usually a blend of 10% alcohol and 90% gasoline (87 octane)  Fuel system modifications are not needed to use gasohol  Alcohol increases antiknock qualities of the gasoline

© Goodheart-Willcox Co., Inc. Gasohol 10% alcohol can increase 87 octane gasoline to 91 octane

© Goodheart-Willcox Co., Inc. Synthetic Fuels  Made from coal, shale oil, or tar sand  “Synthesized” from a solid hydrocarbon state to a liquid or gaseous state  As fuel costs increase, synthetic fuels could become a cost-effective alternative to crude oil pumped from the ground

© Goodheart-Willcox Co., Inc. Synthetic Fuels

© Goodheart-Willcox Co., Inc. Hydrogen  Highly flammable gas  Produced through the electrolysis of water  sending electric current through saltwater  Burns very cleanly, leaving only water and carbon dioxide as by-products  Expensive to make and store

© Goodheart-Willcox Co., Inc. Hydrogen