I.C.E 2 LECTURE 1 difference between gasoline and diesel engines

ice engines

1. I.C.E(2) Lectures
Dr. Iham Zidane

2. 2
Types of Heat Engines
Internal Combustion Engine (I.C.E) External Combustion Engine (E.C.E)
Internal Combustion Engines produce mechanical
power from the chemical energy contained in the
fuel, as a result of the combustion process
occurring inside the engine.
-Combustion process takes place in the cylinder.
❑Gasoline Engine
❑Diesel Engine
❑Gas Turbine
In external combustion engines, the combustion
process takes place outside the mechanical engine
system.
❑Steam Turbine
❑Nuclear

3. 3
I.C Engine Classification
Design shape
(Arrangement)
Reciprocating

4. 4
I.C Engine Classification
Combustion chamber
Design (Arrangement)
Reciprocating
Acting cycle
4-Stroke 2-Stroke
complete cycle in
720°, naturally
aspirated,
supercharged.
complete cycle
in 360°
crankcase
scavenged,
supercharged,
Ignition Method
Spark Ignition Compression ignition
ignition is by the
application of
external energy (
spark plug)
ignition by
compression
Engine speed
Medium (800-
1500 rpm)
High (2500-
8000 rpm)
Low (100-600
rpm)
Cooling Method
Water cooled Air cooled
Charging System
Natural aspiratedSuper charged
Used fuel
Application

5. ICE Cylinder Particulars
L
θ
B
TDC
BDC
B= Bore
L= Stroke
TDC= top dead center
BDC= bottom dead center
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�= Stroke volume
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??????= Clearance volume
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�= Total volume (??????
�+ ??????
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??????= compression ratio
=
????????????
????????????
P.E= 7-12
D.E= 15-24
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�
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�
S
l
a

6. 6
Engine PartsComparison between Petrol Engine (SI engine) and Diesel engine (CI engine)
Feature Petrol Engine High speed Diesel Engine
Admission offuel From carburetorvia the manifold, or
injected into the inlet port
Directly from fuel injector
Compression ratio 7:1-to 10:1 14:1-24:1
Ignition Electric spark Heat due to compression
Torque Low andvaries greatly throughout the
speed range
Highandvaries little throughout the speed
range
Brake thermal efficiency 25-30% 35-43%
Exhaust gases Poisonous Non-Poisonous
, but may cause suffocation
Engine construction Light Robust
RPM 4000 rpm –6000 rpm 2500-5000 rpm
Compression pressure Theoretical at 8:1 CR, 1728 kPa
Actual 750-1400 kPa
Theoretical at 16:1 CR, 4254 kPa
Actual 3100-3800 kPa
Compression temperature Theoretical at 8:1 CR, 375°C
Actual around 230 °C
Theoretical at 16:1 CR, 525°C
Actual 425-550 °C
Fuel used Petrol (Gasoline) Diesel

7. 7
Advantages of Diesel Engine
•Higher thermal efficiency than other heat engines.
•The DE can use a lower quality of fuel which is cheaper than gasoline fuel.
•The DE has less fuel consumption to deliver the same power
•The overhauls, maintenance and repairing processes of DE are simple and common.
•The DE provides big range of power and speed for different applications.
•The DE is a heavy duty and long life engine which work for long time without failure.
•The torque characteristics of a diesel engine does not vary greatly at either high or low speeds.

8. •They generate less waste heat in cooling and exhaust.
•The carbon monoxide content of the exhaust is minimal.
8
Advantages of Diesel Engine (CONT.)

9. 9
Disadvantages of Diesel Engine
1.DEwasoncehardertostartincoldweatherthanpetrolengine.
2.TheDEisslightlygreaterweightcomparetothepetrolengineforthesame
power(higherstresses).
3.ThehighspeedDEprovideshighfrictionlossesinoperationparticularlyat
partialloads.
4.ThereciprocatingcomponentsofDEarisingtheinertialoadswhichincrease
noiseandvibration.
5.ThemodernDEhascomplicatedconstructionandhighinitialcost.

10. 10
Requirements and features of diesel engines
1.TheDEshouldhaveassmallaspossibleofspecificvolume(volume/power)andaslight
aspossibleofspecificweight(weight/power).
2.TheDEshouldproduceveryhighoverallthermalefficiency.
3.TheDEshouldbeheavydutyandoperateforlongperiodwithoutfailure.
4.TheDEshouldhavelowerspecificfuelconsumption.
5.TheDEshouldbeeasyinmaintenanceandrepairwithlongoverhaulperiod.
6.TheDEshouldoperatewithlessnoiseandvibration
7.TheDEshoulddesigntoprovidelessemissionsandpollutions.
8.TheDEhastousealowerqualityoffuelwithlowcost.