Engine type and classification.
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Transcript of Engine type and classification.
ENGINE PARTSCylinder blockCylinder headCrank casePiston Piston ringsGudgeon pin Intake and exhaust valveCamshaftCrankshaftTiming gears
ENGINE CLASSIFICATION
No of strokes per cycle(Two or Four)
Type of fuel burned Method of ignition Firing order Reciprocating or rotary
No of cylinders
Arrangement of cylinders
Arrangement of valves and
valve trains
Type of cooling
POSITION ARRANGEMENT & NUMBER OF CYLINDERS
Single Cylinder
Inline Cylinders
V Engine
‰Opposed Cylinder Engine
‰W Engine
‰Opposed Piston Engine
‰Radial Engine
ARRANGEMENT OF CYLINDERSSingle cylinder:
Engine has one cylinder and piston connected to the crankshaft.
‰In-Line:
Cylinders are positioned in a straight line, one behind the other along the
length of the crankshaft. Number of cylinders may vary
from 2 to 11 or even more. In-line four-cylinder engines
are very common for automobiles. In-line engines are
also referred to as straight such as straight six or straight
eight
.
ARRANGEMENT OF CYLINDERS
V Engine:
Two banks of cylinders at an angle with each other along a single crankshaft.
The angle between the banks of cylinders is usually within 60-90. V engines
have even numbers of cylinders ranging from 2 to 20 or more. V6 and V8
are the common engines with six and eight cylinders respectively.
Opposed Cylinder Engine:
Two banks of cylinders opposite to each other on a single crankshaft. These
are mostly used in small aircraft and some automobiles with an even number
of cylinders from two to eight or more. These engines are also called flat
engines such as flat four.
ARRANGEMENT OF CYLINDERSW Engine:Similar to that of V engine except with three banks of cylinders on the
same crankshaft. This type of arrangement has been used in some racing cars.
Opposed Piston Engine: Two pistons in each cylinder with the combustion chamber located
centrally between the pistons. A single-combustion process causes two power strokes at the same time, with each piston being pushed away from the center and delivering power to a separate crankshaft at each end of the cylinder Engine output is either on two rotating crankshafts or on one crankshaft incorporating a complex mechanic linkage.
ARRANGEMENT OF CYLINDERSRadial Engine:
Engine with pistons positioned in a circular plane around the central
crankshaft. The connecting rods of the pistons are connected to the
crankshaft through a master rod. A bank of cylinders on a radial engine
always has an odd number of cylinders ranging from 3 to 13 or more
Many medium-and large-size propeller-driven aircraft use radial engines.
For large aircraft, two or more banks of cylinders are mounted together,
one behind the other on a single crankshaft, making a powerful and
smooth engine.
VALVE LOCATIONS
‰
Valves in head (overhead valve), also called I-head engine.‰Valves in block (flat head), also called L-head engine. Some historic
engines with valves in block had the intake valve on one side of the cylinder, and the exhaust valve on the other side. These were called T-
head engines.‰One valve in head (usually intake) and one in block, also called F-head engine.
VALVE TRAINS
Times the opening and closing of the cylinder valvesEnsures opening and closing is kept in sync
NO OF STROKES
‰Four Stroke Cycle Experiences 4 strokes of the Piston movements over 2 revolutions of the crankshaft‰Two Stroke Cycle Experiences 2 strokes of the Piston movements over 1 revolution of the crankshaft
FUEL USEDUsing volatile fuels like gasoline, alcohol, kerosene �Using gaseous fuels like natural gas, biogas
�Using viscous fuels like diesel �Using dual fuel methanol (suction stroke) + diesel (comp. stroke) –CI
Engine–gasoline + alcohol (gasohol)
METHOD OF IGNITION
Spark Ignition: An SI engine starts the combustion process in each cycle by
use of a spark plug. In early engine development, before the invention of the electric spark plug, many forms of
torch of torch holes were used to initiate combustion form an external flame.‰Compression Ignition: The combustion process in a CI engine starts when the air-fuel mixture self-ignites due to high temperature in the combustion chamber caused by high compression .