Internal combustion engine manual
INTERNAL COMBUSTION ENGINE MANUAL
BY F. W. STERLING
WASHINGTON, BERESFORD PRINTER, 1917
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Internal combustion engine manual
PREFACE TO FOURTH EDITION.
The fourth edition of this volume, which marks its eighth year as a text book at the Naval Academy, has been completely rewritten, enlarged and brought up to date. The original sequence is still preserved, as it is believed the best for instruction of the uninitiated, viz:
(a) The subject of fuels is first treated fully, this being the fundamental element that governs design and operation. These fuels follow in a natural sequence which order is preserved when carburetion is taken up in Chapter V.
(b) The engine proper naturally divides itself into four systems: (1) fuel system, (2) ignition system, (3) cooling system, (4) lubrication system. These are treated in detail in the above order and in Chapter X the four systems assembled are illustrated by modern commercial engines.
A chapter has been added on the aeroplane engine and the five types, vertical, horizontal opposed, V-type, radial, and rotary are illustrated by up to date American engines.
(a) The subject of fuels is first treated fully, this being the fundamental element that governs design and operation. These fuels follow in a natural sequence which order is preserved when carburetion is taken up in Chapter V.
(b) The engine proper naturally divides itself into four systems: (1) fuel system, (2) ignition system, (3) cooling system, (4) lubrication system. These are treated in detail in the above order and in Chapter X the four systems assembled are illustrated by modern commercial engines.
A chapter has been added on the aeroplane engine and the five types, vertical, horizontal opposed, V-type, radial, and rotary are illustrated by up to date American engines.
CHAPTER I - FUELS.
Selection. The considerations governing the selection of a fuel in general are its accessibility, price, amount available, rate of combustion, and thermal value; it does not naturally follow that these are the only limitations which shall regulate the choice of a fuel for use in an internal combustion engine.
Fuel for use in an internal combustion engine must readily combine with air to form a combustible mixture of gas or vapor, must leave little or no solid residue after combustion, and must have certain thermo-chemical characteristics such as a proper rate of flame propagation, etc. It need not necessarily be of a very high calorific value, as will be shown later, but obviously this is desirable. The fuel is usually a compound of carbon and hydrogen, or a mixture of such compounds, found thus in nature or manufactured.
The General Classification of internal combustion engine fuels is:
1. The solid fuels.
2. The liquid fuels.
3. The gaseous fuels.
Solid fuels cannot be used in an internal combustion engine in their natural state, hence coal and other carbonaceous solids must be gasified to CO and H by partial combustion and volatilization to prepare them for such use. Although the Diesel engine was originally designed to use coal dust for fuel, and experiments have been made along this line, the idea was finally abandoned.
Solid fuels are converted into (a) air gas, (b) water gas, (c) producer gas.
Liquid fuels comprise (a) distillates of petroleum or crude oil, (b) alcohol, and (c) benzol.
The gaseous fuels consist of (a) oil gas, (b) illuminating gas, (c) coke oven gas, (d) blast-furnace gas, (e) natural gas, and (f) acetylene.
Of all these fuels the most important marine fuel is petroleum.
CHAPTER II - GENERAL
An internal combustion engine, as the name implies, is one in which, in contradistinction to the steam engine, combustion of the fuel takes place in the cylinder itself. A steam engine cannot run without a separate unit, the boiler, for the consumption of fuel and generation of steam, the medium of motive power. Hence in the gas engine vernacular it is called an external combustion engine. On the other hand, fuel is fed directly to the cylinder of an internal combustion engine, ignited therein, and the resulting explosion acting on the piston furnishes the motive power.
Progressive Combustion. The internal combustion engine is commonly, though erroneously, called an explosion engine. The action which takes place, and which appears to be an explosion, is in reality a progressive combustion and subsequent expansion of the products of combustion. Some oil engines actually carry the combustion through a considerable part of the stroke. Although the expansion line of an indicator card is necessarily of interest to the manufacturer, the ratio of expansion presents no problem, for the internal combustion engine has no adjustable cut-off, and therefore the ratio of expansion is fixed for a given engine by the clearance space and the space swept by the piston.
The problem of expansion is replaced by questions of rate of combustion, rate of flame propagation, quantity and quality of fuel, and, most important of all, compression.
Compression. The question of compression will be treated at length later, but a word here is necessary to what follows : when a fuel, such as gas, is admitted to the cylinder of an engine, a certain quantity of air is admitted at the same time to furnish the necessary oxygen for combustion. Before ignition this "mixture," as it is called, is compressed into a small space (the "clearance space"). This compression serves to mix the particles of air and fuel more intimately and to raise the temperature of the mixture. The resultant compressed mixture will ignite with more certainty and will burn more evenly than a rarer and colder mixture.
There are four essential systems to every engine, and these are treated at length in subsequent chapters. They are: (1) fuel system; (2) ignition system; (3) cooling system; and (4) oiling system.
Fuel System. This consists of a fuel tank, a strainer for liquid fuels, the carburetor, atomizer, or other agent for converting the fuel to a combustible vapor, and the exhaust, which usually terminates in a muffler. In the case of liquid fuels it is necessary to volatilize and mix them with air before they can be ignited in the cylinder. Fig. 2 illustrates an ordinary gasoline fuel system.
Ignition System. If the ignition is electrical, this system consists of a source of current supply, wiring, and a means of causing a spark to leap a gap, thus forming an arc in the presence of the fuel in the cylinder. The spark thus created ignites the mixture. If the system is not electrical, then it consists of an apparatus designed to bring the combustible mixture in contact with a surface hot enough to ignite it. This is treated in detail under the chapter on ignition.
Cooling System. This consists of artificial means for keeping the cylinder from overheating. It is discussed at length later.
Lubricating System. This is more complex than in the case of the steam engine, as it is necessary to include in the system means of lubricating the insides of the cylinder walls. It is discussed in a later chapter under the subdivisions, internal and external lubrication.
The Four Requisites. As early as 1832 Beau de Rochas announced the four requisites for economical and efficient working of internal combustion engines, and, with one exception, these are undisputed today. They are :
1. The maximum cylinder volume with the minimum cooling surface.
2. The maximum rate of expansion, hence, high speed.
3. The greatest possible pressure at the beginning of expansion, hence, high compression.
4. The greatest possible expansion, hence, long stroke.
Short and Long Stroke. Much discussion has arisen on the merits of the long or short stroke motor. The long stroke gives a greater expansion, but it also increases the duration of contact of the gases with the cylinder walls. This increases the radiation losses. The short stroke decreases the expansion, but it also decreases the radiation losses. This point is discussed later.
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Internal combustion engine manual
Fuel for use in an internal combustion engine must readily combine with air to form a combustible mixture of gas or vapor, must leave little or no solid residue after combustion, and must have certain thermo-chemical characteristics such as a proper rate of flame propagation, etc. It need not necessarily be of a very high calorific value, as will be shown later, but obviously this is desirable. The fuel is usually a compound of carbon and hydrogen, or a mixture of such compounds, found thus in nature or manufactured.
The General Classification of internal combustion engine fuels is:
1. The solid fuels.
2. The liquid fuels.
3. The gaseous fuels.
Solid fuels cannot be used in an internal combustion engine in their natural state, hence coal and other carbonaceous solids must be gasified to CO and H by partial combustion and volatilization to prepare them for such use. Although the Diesel engine was originally designed to use coal dust for fuel, and experiments have been made along this line, the idea was finally abandoned.
Solid fuels are converted into (a) air gas, (b) water gas, (c) producer gas.
Liquid fuels comprise (a) distillates of petroleum or crude oil, (b) alcohol, and (c) benzol.
The gaseous fuels consist of (a) oil gas, (b) illuminating gas, (c) coke oven gas, (d) blast-furnace gas, (e) natural gas, and (f) acetylene.
Of all these fuels the most important marine fuel is petroleum.
CHAPTER II - GENERAL
An internal combustion engine, as the name implies, is one in which, in contradistinction to the steam engine, combustion of the fuel takes place in the cylinder itself. A steam engine cannot run without a separate unit, the boiler, for the consumption of fuel and generation of steam, the medium of motive power. Hence in the gas engine vernacular it is called an external combustion engine. On the other hand, fuel is fed directly to the cylinder of an internal combustion engine, ignited therein, and the resulting explosion acting on the piston furnishes the motive power.
Progressive Combustion. The internal combustion engine is commonly, though erroneously, called an explosion engine. The action which takes place, and which appears to be an explosion, is in reality a progressive combustion and subsequent expansion of the products of combustion. Some oil engines actually carry the combustion through a considerable part of the stroke. Although the expansion line of an indicator card is necessarily of interest to the manufacturer, the ratio of expansion presents no problem, for the internal combustion engine has no adjustable cut-off, and therefore the ratio of expansion is fixed for a given engine by the clearance space and the space swept by the piston.
The problem of expansion is replaced by questions of rate of combustion, rate of flame propagation, quantity and quality of fuel, and, most important of all, compression.
Compression. The question of compression will be treated at length later, but a word here is necessary to what follows : when a fuel, such as gas, is admitted to the cylinder of an engine, a certain quantity of air is admitted at the same time to furnish the necessary oxygen for combustion. Before ignition this "mixture," as it is called, is compressed into a small space (the "clearance space"). This compression serves to mix the particles of air and fuel more intimately and to raise the temperature of the mixture. The resultant compressed mixture will ignite with more certainty and will burn more evenly than a rarer and colder mixture.
There are four essential systems to every engine, and these are treated at length in subsequent chapters. They are: (1) fuel system; (2) ignition system; (3) cooling system; and (4) oiling system.
Fuel System. This consists of a fuel tank, a strainer for liquid fuels, the carburetor, atomizer, or other agent for converting the fuel to a combustible vapor, and the exhaust, which usually terminates in a muffler. In the case of liquid fuels it is necessary to volatilize and mix them with air before they can be ignited in the cylinder. Fig. 2 illustrates an ordinary gasoline fuel system.
Ignition System. If the ignition is electrical, this system consists of a source of current supply, wiring, and a means of causing a spark to leap a gap, thus forming an arc in the presence of the fuel in the cylinder. The spark thus created ignites the mixture. If the system is not electrical, then it consists of an apparatus designed to bring the combustible mixture in contact with a surface hot enough to ignite it. This is treated in detail under the chapter on ignition.
Cooling System. This consists of artificial means for keeping the cylinder from overheating. It is discussed at length later.
Lubricating System. This is more complex than in the case of the steam engine, as it is necessary to include in the system means of lubricating the insides of the cylinder walls. It is discussed in a later chapter under the subdivisions, internal and external lubrication.
The Four Requisites. As early as 1832 Beau de Rochas announced the four requisites for economical and efficient working of internal combustion engines, and, with one exception, these are undisputed today. They are :
1. The maximum cylinder volume with the minimum cooling surface.
2. The maximum rate of expansion, hence, high speed.
3. The greatest possible pressure at the beginning of expansion, hence, high compression.
4. The greatest possible expansion, hence, long stroke.
Short and Long Stroke. Much discussion has arisen on the merits of the long or short stroke motor. The long stroke gives a greater expansion, but it also increases the duration of contact of the gases with the cylinder walls. This increases the radiation losses. The short stroke decreases the expansion, but it also decreases the radiation losses. This point is discussed later.
DOWNLOAD FREE BOOK:
Internal combustion engine manual
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