3. What is an
I.C ENGINE???
Internal Combustion Engine is
a heat engine which converts the heat
energy released by the combustion of fuel
taking place inside the engine cylinder
into mechanical work.
4. CLASSIFICATION OF I.C. ENGINES
1. Nature of Thermodynamic Cycle as:
i. Otto Cycle Engine
ii. Diesel Cycle Engine
iii.Dual Combustion Cycle Engine
2. Type of Fuel used:
i. Petrol Engine
ii. Diesel Engine
iii.Gas Engine
iv.Bi-Fuel Engine
5. 3. Number of strokes as:
i. Four Stroke Engine
ii. Two Stroke Engine
CLASSIFICATION OF I.C. ENGINES
4. Method of Ignition as:
i. Spark Ignition Engine, known as S.I Engine
ii. Compression Ignition Engine, known as C.I
Engine
6. CLASSIFICATION OF I.C. ENGINES
5. Number of Cylinders as:
i. Single Cylinder Engine
ii. Multi-cylinder Engine
6. Method of Cooling as:
i. Air Cooled Engine
ii. Water Cooled Engine
7. CLASSIFICATION OF I.C. ENGINES
7. Position of Cylinder as:
i. Horizontal Engine
ii. Vertical Engine
iii.Vee Engine
iv.Opposed Cylinder Engine
v.Radial Engine
8. Parts of I.C. Engine
1. Cylinder:
Heart of the engine.
Fuel is burnt and power
is developed.
Inside diameter is called
“bore”.
9.
10.
11.
12. Parts of I.C. Engine
2. Piston:
Is a close fitting hollow-
cylindrical plunger.
It reciprocates inside the
cylinder.
Power developed by
combustion of fuel is
transmitted by piston to
crank-shaft through
connecting rod.
13. Parts of I.C. Engine
3. Piston Rings:
Metallic rings inserted
into the circumferential
grooves at top of the
piston.
These rings maintain gas
tight joint between piston
and cylinder.
Also help in conducting
heat from piston to
cylinder.
14. Parts of I.C. Engine
4. Connecting Rod:
Link that connects piston
and crankshaft by means
of pin joints.
Converts rectilinear
motion of piston into
rotary motion of the
crankshaft.
15. Parts of I.C. Engine
5. Crank and Crankshaft:
Crank is the lever
connecting to end of
connecting rod by pin
joint
Other end of crank is
connected rigidly to a
shaft called crankshaft
16. Parts of I.C. Engine
6. Valves:
Devices which control
flow of intake and exhaust
gases to and from engine
cylinder
Also called poppet valves
These valves are operated
by means of cams driven
by crankshaft through a
timing gear or chain.
17. Parts of I.C. Engine
7. Flywheel:
Heavy wheel mounted on
crankshaft of the engine
Helps in maintaining
uniform rotation of the
crankshaft
18. Parts of I.C. Engine
8. Crankcase:
Lower part of the engine
serving an enclosure for
crankshaft
Also a sump for lubricating
oil
19. I C ENGINE
TERMINOLOGY
Bore: Inner diameter of the
engine
Stroke: It is the linear distance
travelled by the piston when it
moves from one end of the
cylinder to the other end. It is
equal to twice the radius of
the crank
20. Cover End or Top Dead
Centre(TDC):
The extreme position near to
the cover or cylinder head of
the engine is called cover
end. In vertical engines, this
extreme position of the
piston is called Top Dead
Centre(TDC).
I C ENGINE
TERMINOLOGY
21. I C ENGINE
TERMINOLOGY
Crank End or Bottom Dead
Centre (BDC):
The extreme position near to
the crank is called crank end.
In vertical engines, this
extreme position of the
piston is called the Bottom
Dead Centre (BDC).
32. PROBLEMS
• A single cylinder two-stroke I.C Engine has
piston diameter 105mm and stroke length
120mm. The mean effective pressure is 6 bar.
If the crank shaft speed is 1500 rpm, calculate
the indicated power of the engine.
33. PROBLEMS
• A four-stroke I.C. Engine running at 450 rpm
has a bore diameter of 100mm and stroke
length 120mm. The indicator diagram details
are: area of the diagram 4cm2, length of
indicator diagram 6.5cm and the spring value
of the spring used is 10 bar/cm. Calculate the
indicated power of the engine.
34. PROBLEMS
• During the test on a four-stroke engine, the following
readings were taken when running at full load,
Area of the indicator diagram = 3 cm2
Length of the indicator diagram = 5 cm
Spring constant = 100 N/cm2/cm
Engine crankshaft speed = 500 rpm
Diameter of the engine cylinder = 150mm
Stroke of the piston = 200mm
Find the indicated power of the engine.
35. PROBLEMS
• A two-stroke diesel engine has a piston
diameter of 200mm and a stroke of 300mm. It
has mean effective pressure of 2.8 bar and
speed of 400 rpm. The diameter of the brake
drum is 1 meter and the mean effective brake
load is 64kg. Find the indicated power, the
brake power, the mechanical efficiency of the
engine and the average piston speed.
36. PROBLEMS
1. Brake Power
2. Indicated Power
3. Friction Power
1. Mechanical Efficiency
2. Brake Thermal Efficiency
3. Indicated Thermal Efficiency
•The following observations were obtained during a trial on
a four-stroke diesel engine.
Cylinder diameter = 25cm
Stroke of the Piston = 40cm
Crankshaft speed = 250rpm
Brake load = 70kg
Brake drum diameter = 2m
Mean effective pressure = 6 bar
Diesel oil consumption = 0.1m3/min
Specific gravity of diesel = 0.78
Calorific value of diesel = 43900 kJ/kg
Find:
