25. ENGINE CLASSIFICATION
๏ข No of strokes per cycle(Two
or Four)
๏ข Type of fuel burned
๏ข Method of ignition
๏ข Firing order
๏ข Reciprocating or rotary
๏ข No of cylinders
๏ข Arrangement of cylinders
๏ข Arrangement of valves and
valve trains
๏ข Type of cooling
26. POSITION ARRANGEMENT &
NUMBER OF CYLINDERS
๏ข Single Cylinder
๏ข Inline Cylinders
๏ข V Engine
๏ข โฐOpposed Cylinder Engine
๏ข โฐW Engine
๏ข โฐOpposed Piston Engine
๏ข โฐRadial Engine
28. ARRANGEMENT OF CYLINDERS
Single cylinder:
Engine has one cylinder and piston connected to the crankshaft.
โฐIn-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
29.
30. 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.
33. ARRANGEMENT OF CYLINDERS
W 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.
34. ARRANGEMENT OF CYLINDERS
Radial 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.
48. VALVE LOCATIONS
๏จ โฐ
Valves in head (overhead valve), also called I-head engine
.
โฐ
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.
โฐ
One valve in head (usually intake) and one in
block, also called F-head engine
.
54. NO OF STROKES
โฐ
Four Stroke Cycle Experiences 4 strokes
of the Piston movements over 2 revolutions
of the crankshaft
โฐ
Two Stroke Cycle Experiences 2 strokes
of the Piston movements over 1 revolution
of the crankshaft
55. FUEL USED
Using volatile fuels like gasoline, alcohol, kerosene โฐ
Using gaseous fuels like natural gas, biogas
โฐ
Using viscous fuels like diesel
โฐ
Using dual fuel
methanol (suction stroke) + diesel (comp. stroke) โCI
Engine
โgasoline + alcohol (gasohol)
56. 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.
โฐ
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
๏จ .