The four-stroke petrol engine operates via four strokes: the intake stroke, compression stroke, power stroke, and exhaust stroke. Alphonse Beau de Rochas first patented the four-stroke engine design in 1861, though others had worked on similar ideas. Nikolaus Otto built the first car with a four-stroke engine in 1876. Four-stroke engines have advantages of more torque, longer lifespan, and cleaner running compared to two-stroke engines, though they are more complex, less powerful, and expensive. The engine draws in air and fuel during the intake stroke, compresses it during the compression stroke, burns it during the power stroke, and expels exhaust during the exhaust stroke.

1.  Introduction
 History
 Advantage and Disadvantage of 4 stroke petrol
engine
 Working of 4 stroke petrol engine
 Reference

2.  A four-stroke engine (also known as four cycle) is an
internal combustion engine in which the piston
completes four separate stroke which constitute a
single thermodynamic cycle. A stroke refers to the
full travels of the piston along the cylinder, in either
direction. The four separate strokes are termed:
1. Intake Stroke
2. Compression Stroke
3. Power Stroke
4. Exhaust Stroke

3.  The four-stroke engine was first patented by Alphonse
Beau de Rochas in 1861. Before, in about 1854-57, two
italians (Eugenio Barsanti and Felice Matteucci) invented
an engine that was rumored to be very similar, but the
patent was lost.
 The first person to actually build a car with this engine
was german engineer Nikolaus otto in 1876. That’s why
the four stroke principle today is commonly known as
the otto cycle and four stroke engine using spark plug
often are called otto engines. The otto cycle consists of
adiabatic compression, heat addition at const. volume. In
the case of a four-stroke otto cycle, there are also an
isoberic compression and an isoberic expansion, usually
ignored since in an idealized process those do not play
any role in the heat intake or work output.

4.  More torque
 Last longer
 Run much cleaner
then two stroke
 More efficient use
of gas
 Complicated
 Half as powerful
as two stroke
engine
 More expansive
then two stroke

6.  Intake valve open
 Exhaust valve
closed
 Piston go to TDC to
BDC
 Air-fuel mixture
enter in to the
cylinder

7.  Intake valve closed
 Exhaust valve
closed
 Piston go to BDC to
TDC
 Air-fuel mixture
compressed in to
the cylinder

8.  Intake valve closed
 Exhaust valve
closed
 Air-fuel mixture
burn into the
combustion
chamber
 Piston go to TDC to
BDC

9.  Intake valve closed
 Exhaust valve open
 Piston go to BDC to
TDC
 Exhaust gas out
through the
exhaust valve

10. 1. www.google.co.in
2. www.wikipedia.com