simple review on ic engine

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3.  Internal-combustion engine, one in which
combustion of the fuel takes place in a confined
space, producing expanding gases that are used
directly to provide mechanical power. Such engines
are classified as reciprocating or rotary, spark ignition
or compression ignition, and two-stroke or four-
stroke; the most familiar combination, used from
automobiles to lawn mowers, is the reciprocating,
spark-ignited, four-stroke gasoline engine. Other
types of internal-combustion engines include the
reaction engine (see jet propulsion, rocket), and the
gas turbine. Engines are rated by their maximum
horsepower, which is usually reached a little below the
speed at which undue mechanical stresses are
developed.
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4.  Invented in early 1680
 First attempt by Christian Huygens
 Converts heat energy produced by burning of fuel
to mechanical output.
 Basically consists of a piston-cylinder
arrangement.
 The expansion of air due to the heat produced
moves the piston inside the cylinder.
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5.  The first two stroke engine design was a diesel
engine by Dugald Clark in 1878, and used a similar
cylinder heat to a four –stroke diesel engine, and a
supercharger.
 The gasoline two stroke engine, and the cylinder
parts on which it depends were invented by Joseph
Day in 1889. These cylinder parts were
subsequently incorporated into diesel two-stroke
engines, replacing either just inlet valves or both inlet
and exhaust valves.
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6.  1. According to thermodynamic cycle
 i) Otto cycle engine or Constant volume heat supplied cycle.
 ii) Diesel cycle engine or Constant pressure heat supplied cycle
 iii) Dual-combustion cycle engine
 2. According to the fuel used:
 i) Petrol engine ii) Diesel engine iii) Gas engine
 3. According to the cycle of operation:
 i) Two stroke cycle engine ii) Four stroke cycle engine
 4. According to the method of ignition:
 i) Spark ignition (S.I) engine ii) Compression ignition (C I )
engine
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7.  5. According to the number of cylinders.
 i) Single cylinder engine ii) Multi cylinder engine
 6. According to the arrangement of cylinder:
 I) Horizontal engine ii) Vertical engine iii) V-engine
 v) In-line engine vi) Radial engine, etc.
 7. According to the method of cooling the
cylinder:
 I) Air cooled engine ii) Water cooled engine
 8. According to their applications:
 i) Stationary engine ii) Automobile engine iii) Aero
engine
 iv) Locomotive engine v) Marine engine, etc.
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8. The internal combustion engine is
an engine in which the combustion
of fuel-oxidizer mixture occurs in a
confined space
applied in:
automotive
rail transportation
power generation
ships
aviation
garden appliances 6
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9. In internal combustion engine
combustion of fuel takes place inside the
engine cylinder. Power is generated
intermittently (only during power stroke)
and flywheel is used to provide uniform
output torque. Usually these engines are
reciprocating engines. The reciprocating
engine mechanism consists of piston
which moves in a cylinder and forms a
movable gas tight seal. By means of a
connecting rod and a crank shaft
arrangement, the reciprocating motion of
piston is converted into a rotary motion of
the crankshaft. They are most popular
because of their use as main prime mover in
commercial vehicles.
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10. The four-stroke cycle petrol engines operate
on Otto (constant volume) cycle shown in
Figure 3.0. Since ignition in these engines is
due to a spark, they are also called spark
ignition engines. The four different strokes
are:
 i) Suction stroke
 ii) Compression stroke
 iii) Working or power or expansion
stroke
 iv) Exhaust stroke.
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11.  Suction Stroke : During suction stroke, the piston is moved
from the top dead centre to the bottom dead centre by the
crank shaft. The crank shaft is revolved either by the
momentum of the flywheel or by the electric starting
motor. The inlet valve remains open and the exhaust
valve is closed during this stroke. The proportionate
air-petrol mixture is sucked into the cylinder due to
the downward movement of the piston.
• Compression Stroke: During compression stroke, the piston
moves from bottom dead centre to the top dead centre, thus
compressing air petrol mixture. Due to compression,
the pressure and temperature are increased Just
before the end of this stroke the spark – plug
initiates a spark, which ignites the mixture and
combustion takes place at constant volume.
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12. • Working Stroke: The expansion of hot gases exerts a pressure on
the piston. Due to this pressure, the piston moves from top dead
centre to bottom dead centre and thus the work is obtained in this
stroke. Both the inlet and exhaust valves remain closed during this
stroke.
 Exhaust Stroke: During this stroke, the inlet valve remains closed
and the exhaust valve opens. The greater part of the burnt gases
escapes because of their own expansion. The piston moves from
bottom dead centre to top dead centre and pushes the remaining
gases to the atmosphere. When the piston reaches the top dead
centre the exhaust
valve closes and cycle is completed. The
operations are repeated over and over
again in running the engine. Thus a four
stroke engine completes one working cycle,
during this the crank rotate by two
revolutions.
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14.  Since the two stroke engine fires on every revolution of
the crankshaft, a two stroke engine is usually more
powerful than a four stroke engine of equivalent size.
This, coupled with their lighter, simpler construction
makes two stroke engines popular in chainsaws, line
trimmers, outboard motors, snowmobiles, jet-skis,
light motor cycles, and model airplanes.
 Unfortunately most two strokes engines are inefficient
and are terrible polluters due to the amount of
unspent fuel that escapes through the exhaust port.
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16. • Top Dead Center (TDC): Position of the piston when it
stops at the furthest point away from the crankshaft.
– Top because this position is at the top of the
engines (not always), and dead because the piston
stops as this point. Because in some engines TDC
is not at the top of the
engines(e.g: horizontally opposed engines, radial
engines, etc,.) Some sources call this position Head End
Dead Center (HEDC).
– Some source call this point TOP Center (TC).
– When the piston is at TDC, the volume in the
cylinder is a minimum called the clearance
volume.
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17. • Bottom Dead Center (BDC): Position of the piston
when it stops at the point closest to the crankshaft.
– Some sources call this Crank End Dead Center
(CEDC) because it is not always at the bottom of
the engine. Some source call this point Bottom
Center (BC).
• Stroke : Distance traveled by the piston from one extreme
position to the other : TDC to BDC or BDC to TDC.
• Bore :It is defined as cylinder diameter or piston face
diameter; piston face diameter is same as cylinder
diameter( minus small clearance).
• Swept volume/Displacement volume : Volume
displaced by the piston as it travels through one stroke.
– Swept volume is defined as stroke times bore.
– Displacement can be given for one cylinder or entire
engine (one cylinder times number of cylinders).
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18. • Clearance volume : It is the minimum volume
of the cylinder available for the charge (air or air
fuel mixture) when the piston reaches at its
outermost point (top dead center or outer dead
center) during compression stroke of the cycle.
– Minimum volume of combustion
chamber with piston at TDC.
• Compression ratio : The ratio of total volume
to clearance volume of the cylinder is the
compression ratio of the engine.
– Typically compression ratio for SI
engines varies form 8 to 12 and for CI
engines it varies from 12 to 24
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20. Figure2: Engine components
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21.  I.C. Engine components shown in figure1 and figure2 are defined
as follows:
• Block : Body of the engine containing cylinders, made of
cast iron or aluminium.
• Cylinder : The circular cylinders in the engine block in
which the pistons reciprocate back and forth.
• Head : The piece which closes the end of the cylinders,
usually containing part of the clearance volume of the
combustion chamber.
• Combustion chamber: The end of the cylinder between
the head and the piston face where combustion occurs.
– The size of combustion chamber continuously changes from
minimum volume when the piston is at TDC to a maximum
volume when the piston at BDC.
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22. • Crankshaft : Rotating shaft through which engine work
output is supplied to external systems.
– The crankshaft is connected to the engine block
with the main bearings.
– It is rotated by the reciprocating pistons through
the connecting rods connected to the crankshaft,
offset from the axis of rotation. This offset is
sometimes called crank throw or crank radius.
• Connecting rod : Rod connecting the piston with the
rotating crankshaft, usually made of steel or alloy forging
in most engines but may be aluminum in some small
engines.
• Piston rings: Metal rings that fit into circumferential
grooves around the piston and form a sliding surface
against the cylinder walls.
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23. • Camshaft : Rotating shaft used to push open
valves at the proper time in the engine cycle,
either directly or through mechanical or hydraulic
linkage (push rods, rocker arms, tappets) .
• Crankcase : Part of the engine block
surrounding the crankshaft.
– In many engines the oil pan makes up part
of the crankcase housing.
• Exhaust manifold : Piping system which carries
exhaust gases away from the engine cylinders,
usually made of cast iron .
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24. • Intake manifold :Piping system which delivers
incoming air to the cylinders, usually made of
cast metal, plastic, or composite material.
– In most SI engines, fuel is added to the air in
the intake manifold system either by fuel
injectors or with a carburetor.
– The individual pipe to a single cylinder is
called runner.
• Spark plug : Electrical device used to initiate
combustion in an SI engine by creating high
voltage discharge across an electrode gap.
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25. Inline Engine
V Type Engine
Flat Engine
Radial Engine
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26.  Each downward stroke of the piston is a power stroke
 Each upward stroke of the piston is a compression
stroke
 The intake and exhaust cycle may be considered a part
of the power and compression stroke and begins after
completion of the power stroke as the exhaust valves
open.
 The intake and exhaust cycle ends after the piston
closes off the intake ports of the cylinder liner on the
compression stroke.
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27.  Greater mechanical simplicity.
 Higher power output per unit weight because of
absence of auxiliary units like boiler , condenser and
feed pump
 Low initial cost
 Higher brake thermal efficiency as only a small
fraction of heat energy of the fuel is dissipated to
cooling system
 These units are compact and requires less space
 Easy starting from cold conditions
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28.  I C engines cannot use solid fuels which are cheaper.
Only liquid or gaseous fuel of given specification can
be efficiently used. These fuels are relatively more
expensive.
 I C engines have reciprocating parts and hence
balancing of them is problem and they are also
susceptible to mechanical vibrations.
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29.  New technologies are needed to improve efficiency of
gasoline and diesels.
• Engines need to be optimized to balance emissions, fuel cost,
and market competitiveness.
• Development of predictive models for engine physical
processes has been an additional enabling factor for advanced
concepts in engine design.
• New low temperature combustion (LTC) concepts, such as:
 Homogeneous Charge Compression Ignition (HCCI),
 Premixed Charge Compression Ignition (PCCI) and
 Reactivity Controlled Compression Ignition (RCCI), …….
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30. • Crouse WH, and Anglin DL,
(1985),
 (Automotive Engine), Tata McGraw Hill.
 P.K NAG (Tata McGraw Hill)
 Heisler H, (1999), Vehicle and engine Technology, Arnold
 www.wikipedia.com
 www.eng.fsu.edu
 www.slideshare.com
 www.mne.psu.edu/simpson/cources
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