Petrol engine vs diesel engine

Introduction to petrol and diesel engine

1. PETROL ENGINE
VS
DIESEL ENGINE
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2. THE BASICS

A four-stroke engine:
Is an internal combustion engine
Converts gasoline into motion
Is the most common car engine type
Is relatively efficient
Is relatively inexpensive

3. PETROL ENGINE

4. 4
A petrol engine is an internal
combustion engine with spark-
ignition, designed to run on petrol
(gasoline) and similar volatile fuels.
 It was invented in 1876 in
Germany by German
inventor Nikolaus August Otto.
 The process differs from a diesel
engine in the method of mixing the
fuel and air, and in using spark plugs
to initiate the combustion process. 
INTRODUCTION

5. Four Stroke Cycle
Intake
Compression
Power
Exhaust
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6. Intake Stroke
Intake valve opens.
Piston moves down, ½
turn of crankshaft.
A vacuum is created in
the cylinder.
Atmospheric pressure
pushes the air/fuel
mixture into the
cylinder.
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7. Compression Stroke
Valves close.
Piston moves up, ½
turn of crankshaft.
Air/fuel mixture is
compressed.
Fuel starts to
vaporize and heat
begins to build.
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8. Power Stroke
Valves remain closed.
Spark plug fires
igniting fuel mixture.
Piston moves down,
½ turn of crankshaft.
Heat is converted to
mechanical energy.
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9. Exhaust Stroke
Exhaust valve opens.
Piston move up,
crankshaft makes ½
turn.
Exhaust gases are
pushed out polluting
the atmosphere.
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11. INTRODUCTION

Invented by Rudolf Diesel
 The diesel engine (also known as a
compression-ignition engine)
is an internal combustion engine.
 in which ignition of the fuel that has been injected
into the combustion chamber by injector.
It has the highest thermal efficiency due to its very
high compression ratio.
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12. Intake Stroke:
•Piston moves from TDC to BDC
creating vacuum in the cylinder
•Intake valve opens allowing only
air to enter the cylinder and
exhaust valve remains closed

13. Compression Stroke
•Both valves stay closed
•Piston moves from BDC to TDC,
compressing air to 22:1
•Compressing the air to this extent
increases the temperature inside the
cylinder to above 1000 degree F.

14. Power Stroke
•Both valves stay closed
•When the piston is at the end of
compression stroke(TDC) the injector
sprays a mist of diesel fuel into the
cylinder.
•When hot air mixes with diesel fuel
an explosion takes place in the cylinder.
•Expanding gases push the piston
from TDC to BDC

15. Exhaust Stroke
•Piston moves from BDC to
TDC
•Exhaust valve opens and the
exhaust gases escape
•Intake valve remains closed

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20. The only difference between diesel engine and a four-stroke
gasoline engine is:
•No sparkplug on Diesel engine.
•Has a higher compression ratio.
(14:1 to 25:1)
•Better fuel mileage.

21. ADVANTAGES
1. Diesels are more efficient. Most gasoline engines 
convert about 30 percent of their fuel energy into 
actual power. A traditional diesel converts about 45 
percent. And advanced diesels can hit about 50 
percent.
2. Diesels are more reliable. Because they don’t 
need high-voltage ignition systems, diesel engines 
never fail for lack of a spark. They also don’t emit 
radio frequency emissions that can interfere with a 
vehicle’s other electronic systems.
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3. Diesels run cooler. Because they are more
efficient, diesel engines release less waste heat while
in operation.
4. Diesels last longer. Diesel engine parts are
generally stronger than gas engine components, and
diesel fuel has superior lubricating properties. As a
result, diesel engines tend to last twice as long as gas-
powered ones.
5. Diesel fuel is safer. Diesel fuel doesn’t release
fumes like gasoline does. It’s more difficult to burn and
won’t explode like its lighter counterpart.

23. 6. Diesels are more easily turbo-charged. Put under 
sufficient pressure, gasoline engines will 
spontaneously detonate. By contrast, the amount of 
super- or turbo-charging pressures diesel engines can 
endure are limited only by the strength of the engines 
themselves.
7. Diesels produce minimal carbon monoxide. This 
makes diesel generators useful in mines and 
submarines, environments in which gasoline engine 
exhaust would prove deadly.
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24. 1. Diesel engines, because they have much
higher compression ratios (20:1 for a typical
diesel vs. 8:1 for a typical gasoline engine), as
compare to gasoline engine.
2. Diesel engines also more expensive.
3. Diesel engines, because of the weight and
compression ratio, tend to have lower maximum
RPM ranges than gasoline engines .
DISADVANTAGES

25. 4. This makes diesel engines high torque rather
than high horsepower, and that tends to make
diesel cars slow in terms of acceleration.
5. Diesel engines must be fuel injected, and in
the past fuel injection was expensive and less
reliable
6. Diesel engines tend to produce more smoke
and "smell funny".

26. 7. Diesel engines are harder to start in cold
weather, and if they contain glow plugs, diesel
engines can require you to wait before starting
the engine so the glow plugs can heat up.

8. Diesel engines are much noisier and tend to
vibrate.
9. Diesel fuel is less readily available than gasoline

27. APPLICATION
Passenger cars-
   Diesel engines have long been popular in bigger cars 
and have been used in smaller cars
Other transport uses-
Larger transport applications (trucks, buses, etc.) also 
benefit from the Diesel's reliability and high torque 
output.
Non Transport Uses-
generators, irrigation pumps,
 
corn grinders