This document provides an overview of the key components and functioning of a 4-stroke petrol engine. It describes the cylinder block, piston and rod assembly, crankshaft, piston configurations, valve train types, engine displacement, definitions of terms like TDC and stroke, the four stroke cycle of intake, compression, power, and exhaust strokes, ignition types, camshafts, and the individual functioning of each stroke. It concludes that 4-stroke engines provide more efficiency than 2-stroke engines and are commonly used in vehicles, achieving 40-60% efficiency.

1. 4 STROKE PETROL
ENGINE
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Enrollment no.
116120319018
116120319019
116120319020
Name
Tapan T. Joshi
Parth V. Limbachiya
Kamlesh V. Barapatre

2. CYLINDER BLOCK
The cylinder block
is the foundation to
which all other
components are
attached.

3. PISTON and ROD
Cast Piston
Forged Piston
Barrel Skirt
Slipper Skirt
Two
compression
rings
One oil ring

4. CRANKSHAFT
Changes
Reciprocating
motion to
Rotating
motion

5. PISTON CONFIGURATIONS
Inline 6
Inline 4
Opposed 4
V-6
V-8

6. OTHER ENGINE ID’S
Valve Train Type
Flathead
Overhead Valve (OHV)
Overhead Cam (OHC) or (SOHC)
Dual Overhead Cam (DOHC)
Engine Displacement
Know conversion Factors From CI to CC
CC to CI

7. DEFINITIONS
TDC
STROKE
Top Dead Center
TDC to BDC
Piston at top of
BDC to TDC
stroke.
BDC
Bottom Dead Center
Piston at Bottom of
stroke.
180 degrees of
crankshaft rotation
FOUR CYCLE
(Stroke)
4 x 180 = 720 degrees
to make one
complete cycle.

8. FOUR STROKE CYCLE
Intake
Compression
Power
Exhaust

9. IGNITION
Spark Ignition (SI)
Gasoline Engines use a precisely timed electric spark to
start the combustion process.
Compression Ignition (CI)
Diesel Engines use the heat produced from
compression to raise cylinder temperature above the
flash point of diesel, and inject fuel directly into the
cylinder.

10. CAMSHAFTS
Camshafts turn at one half
crankshaft speed.
Camshafts can be driven
with a gear, chain and
sprocket, or toothed belt.
Camshafts have one lobe
for each valve.

11. INTAKE STROKE
Intake valve open
Exhaust valve closed
piston traveling down from
TDC to BDC
Air is being force into the
cylinder by the difference
between atmospheric and
cylinder pressure

12. COMPRESSION
STROKE
Both valves closed
Piston traveling up BDC to
TDC
Compressing the air-fuel
mixture

13. POWER
STROKE
Both valves closed
Spark plug ignites the
air fuel mixture
Piston is being pushed
down by the expanding
gases from TDC to BDC

14. EXHAUST
STROKE
Exhaust valve open
Intake valve closed
Piston traveling up from
BDC to TDC forcing the
burnt exhaust gases from
the cylinder

15. At TDC the engine has returned to its
starting point.
This type of engine gives practically
more efficiency than 2 stroke engine.
More volumetric efficiency.
Used in bike,car,engines,idustries,etc..
It is internal combustion engine.
Mostly gives 40 to 60% efficiency in a
vehicles.

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References:A book by Atul Prakashan by
:-
A book S.Chand Prakashan by
:www.engineerstudent.co.uk
www.wikipedia.org
www.virtuallab.com
www.engineering.myindialist.com
www.google.com
C.M.Desai
R.S.Khurmi