Internal Combustion Engine
Chapter 11 Internal Combustion Engines
11.1 Introduction Internal combustion engines differ from external combustion engines in that the energy released from the burning of fuel occurs inside the engine rather than in a separate combustion chamber. Examples of external combustion engines are gas and steam turbines. The gas turbine power plant utilizes products of combustion from a separate combustor as the working fluid. These gases are used to drive the gas turbine and produce useful power. The steam power plant utilizes a separate boiler for burning fuels and creating hot gases which convert water to steam. The steam drives the steam turbine to produce useful power. On the other hand, internal combustion engines usually burn gasoline or diesel fuel inside the engine itself. If they use gasoline, they are called spark-ignition engines, since the spark from a spark plug ignites a mixture of air and gasoline trapped in the cylinder of the engine. The spark ignition (SI) engine operates ideally on the Otto cycle. The diesel engine, also called the combustion ignition (CI) engine, burns diesel fuel which is ignited as it is injected into the cylinder filled with very hot compressed air. Although there are some rotary internal combustion engines, internal combustion engines are usually reciprocating engines. Spark ignition engines usually use gasoline mixed with air, and these form the products of combustion upon being ignited. The high-pressure gases formed during combustion of the fuel and air provide impetus to the mobile pistons which reciprocate in cylinders. The pistons are connected to a rotating shaft, the crankshaft, by means of a connecting rod, which is connected at one end to the wrist pin located in the interior of the piston and at the other end to the crank pin of the crankshaft. As the crankshaft rotates through 360 degrees, the piston moves from the top of the cylin-
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Copyright n 1999 by Marcel Dekker, Inc. All Rights Reserved.
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11.1 Introduction Internal combustion engines differ from external combustion engines in that the energy released from the burning of fuel occurs inside the engine rather than in a separate combustion chamber. Examples of external combustion engines are gas and steam turbines. The gas turbine power plant utilizes products of combustion from a separate combustor as the working fluid. These gases are used to drive the gas turbine and produce useful power. The steam power plant utilizes a separate boiler for burning fuels and creating hot gases which convert water to steam. The steam drives the steam turbine to produce useful power. On the other hand, internal combustion engines usually burn gasoline or diesel fuel inside the engine itself. If they use gasoline, they are called spark-ignition engines, since the spark from a spark plug ignites a mixture of air and gasoline trapped in the cylinder of the engine. The spark ignition (SI) engine operates ideally on the Otto cycle. The diesel engine, also called the combustion ignition (CI) engine, burns diesel fuel which is ignited as it is injected into the cylinder filled with very hot compressed air. Although there are some rotary internal combustion engines, internal combustion engines are usually reciprocating engines. Spark ignition engines usually use gasoline mixed with air, and these form the products of combustion upon being ignited. The high-pressure gases formed during combustion of the fuel and air provide impetus to the mobile pistons which reciprocate in cylinders. The pistons are connected to a rotating shaft, the crankshaft, by means of a connecting rod, which is connected at one end to the wrist pin located in the interior of the piston and at the other end to the crank pin of the crankshaft. As the crankshaft rotates through 360 degrees, the piston moves from the top of the cylin-
TM
Copyright n 1999 by Marcel Dekker, Inc. All Rights Reserved.
der
References: Heywood, J.B. (1988). Internal Combustion Engine Fundamentals. New York: McGraw-Hill. Moran, M.J. and Shapiro, H.N. (1992). Fundamentals of Engineering Thermodynamics. New York: Wiley. Ohta, T. (1994). Energy Technology: Sources, Systems and Frontier Conversion. Oxford: Elsevier.