A brief explanation of both two stroke engine and four stroke engine with appropriate figures. It can also submitted to professor at the time of submission.
PPT describes the engine performance parameters of the I.C. engine.
Engine performance is an indication of the degree of success of the engine performs its assigned task, i.e. the conversion of the chemical energy contained in the fuel into the useful mechanical work. The engine performance is indicated by the term efficiency, η. Five important engine efficiencies and other related engine performance parameters are:
Power
Indicated Thermal Efficiency (ηith)
Brake Thermal Efficiency (ηbth)
Mechanical Efficiency (ηm)
Volumetric Efficiency (ηv)
Relative Efficiency or Efficiency Ratio (ηrel)
Mean Effective Pressure (Pm)
Specific Fuel Consumption (sfc)
Fuel-Air or Air-Fuel Ratio (F/A or A/F)
Calorific Value (CV)
Power:-
The main purpose of running an engine is to obtain mechanical power.
Brake Power (B.P.)
The power developed by an Engine at the output shaft is called the brake power.
Brake Power= Brake Workdone/Time
B.P.=BWD/sec.
Indicated power (I.P.)
The total power developed by Combustion of fuel in the combustion chamber is called indicated power.
Indicated Power= Indicated Workdone/Time
I.P.=IWD/sec.
Frictional Power (F.P.)
The difference between I.P. and B.P. is called frictional power (f.p.).
FP = IP – BP
Thermal Efficiency (ηth)
Thermal efficiency is the ratio of Power to energy supplied by the fuel.
ηth= Power/ Energy
In I.C. Engine, thermal efficiency can be classified into two categories i.e.
Indicated Thermal Efficiency (ηith)
Indicated thermal efficiency is the ratio of indicated power to the heat supplied or added.
ηith= IP/Qs
2. Brake Thermal Efficiency (ηith)
Brake Thermal Efficiency is the ratio of brake power to the heat supplied or added.
ηbth= BP/Qs
Volumetric Efficiency (ηv)
This is one of the most important parameters which decide the performance of four-stroke engines. Four stoke engines have distinct suction stoke, volumetric efficiency indicates the breathing ability of the engine.
Volumetric efficiency is defined as the ratio of actual flow rate of air into the intake system to rate at which the volume is displaced by the system.
ηv= (푚 ̇"a/a" )/(푉푑푖푠푝푎푐푒푑 푋 푁/2)
"a"= Inlet density is taken atmospheric air density
N= Number of the cylinder in use
A brief explanation of both two stroke engine and four stroke engine with appropriate figures. It can also submitted to professor at the time of submission.
PPT describes the engine performance parameters of the I.C. engine.
Engine performance is an indication of the degree of success of the engine performs its assigned task, i.e. the conversion of the chemical energy contained in the fuel into the useful mechanical work. The engine performance is indicated by the term efficiency, η. Five important engine efficiencies and other related engine performance parameters are:
Power
Indicated Thermal Efficiency (ηith)
Brake Thermal Efficiency (ηbth)
Mechanical Efficiency (ηm)
Volumetric Efficiency (ηv)
Relative Efficiency or Efficiency Ratio (ηrel)
Mean Effective Pressure (Pm)
Specific Fuel Consumption (sfc)
Fuel-Air or Air-Fuel Ratio (F/A or A/F)
Calorific Value (CV)
Power:-
The main purpose of running an engine is to obtain mechanical power.
Brake Power (B.P.)
The power developed by an Engine at the output shaft is called the brake power.
Brake Power= Brake Workdone/Time
B.P.=BWD/sec.
Indicated power (I.P.)
The total power developed by Combustion of fuel in the combustion chamber is called indicated power.
Indicated Power= Indicated Workdone/Time
I.P.=IWD/sec.
Frictional Power (F.P.)
The difference between I.P. and B.P. is called frictional power (f.p.).
FP = IP – BP
Thermal Efficiency (ηth)
Thermal efficiency is the ratio of Power to energy supplied by the fuel.
ηth= Power/ Energy
In I.C. Engine, thermal efficiency can be classified into two categories i.e.
Indicated Thermal Efficiency (ηith)
Indicated thermal efficiency is the ratio of indicated power to the heat supplied or added.
ηith= IP/Qs
2. Brake Thermal Efficiency (ηith)
Brake Thermal Efficiency is the ratio of brake power to the heat supplied or added.
ηbth= BP/Qs
Volumetric Efficiency (ηv)
This is one of the most important parameters which decide the performance of four-stroke engines. Four stoke engines have distinct suction stoke, volumetric efficiency indicates the breathing ability of the engine.
Volumetric efficiency is defined as the ratio of actual flow rate of air into the intake system to rate at which the volume is displaced by the system.
ηv= (푚 ̇"a/a" )/(푉푑푖푠푝푎푐푒푑 푋 푁/2)
"a"= Inlet density is taken atmospheric air density
N= Number of the cylinder in use
This is a second slide in the IC engine series. Here you will learn about different components of IC engines. All the slides have beautiful graphics for better understanding.
Do you know what is engine, how many types of engines are available now. How conversion of energy takes place from chemical energy to mechanical energy or useful work. Here engine classified according to their combustion, working stroke, arrangement of piston, fuel used for combustion and on the basis of ignition system. 4-stroke petrol engine and 4-stroke diesel engine are described briefly with all 4-strokes which are completed during power conversion process. 2-stroke engine or scooter engine is also described briefly with the complete details of combustion, charge( petrol,diesel ) filling process and how all 4 stroke process(suction, combustion,power stroke, exhaust) completed in 2 stroke engine.
A brief explanation of both two stroke diesel engine and two stroke petrol engine with appropriate figures. It can also submitted to professor at the time of submission.
This is a second slide in the IC engine series. Here you will learn about different components of IC engines. All the slides have beautiful graphics for better understanding.
Do you know what is engine, how many types of engines are available now. How conversion of energy takes place from chemical energy to mechanical energy or useful work. Here engine classified according to their combustion, working stroke, arrangement of piston, fuel used for combustion and on the basis of ignition system. 4-stroke petrol engine and 4-stroke diesel engine are described briefly with all 4-strokes which are completed during power conversion process. 2-stroke engine or scooter engine is also described briefly with the complete details of combustion, charge( petrol,diesel ) filling process and how all 4 stroke process(suction, combustion,power stroke, exhaust) completed in 2 stroke engine.
A brief explanation of both two stroke diesel engine and two stroke petrol engine with appropriate figures. It can also submitted to professor at the time of submission.
this presentation explains the engine components and 4 stroke cycle engine operations. it also includes other activities that might help the students in understanding the 4 stroke cycle engine operation.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
6. Size of Engine
The size of engine is sum of volumes of all cylinders.
PISTON
Measured in cubic centimeters (cc)
Bigger Size (cc) = higher amount of power generation.
7. SOHC
DOHC
•Better than push rods
•One cam each for inlet & exhaust valves
•Single cam controls all valves
•More precise than SOHC setup
9. Topics covered
I.C. Engines
Introduction of I.C. Engines
Classification of I.C. Engines
Constructional details of I.C. Engine
Comparison of Two-stroke and Four-stroke Cycle Engine
Working of two stroke and four stroke diesel
and petrol engines
Comparison of Petrol and Diesel Engine
10. Introduction of I.C. Engine
Heat Engines - A machine or device which derives heat from the
combustion of fuel and converts part of this energy into
mechanical work is called a heat engine. Heat engines may be
classified into two main classes as follows:
1. External combustion engines
2. Internal combustion engines.
11. Introduction of I.C. Engine
Internal Combustion Engines –
In this case, combustion of fuel with oxygen of the air occurs
within the cylinder of the engine. The internal combustion
engines group includes engines employing mixtures of
combustible gases and air, known as gas engines, those using
lighter liquid fuel or spirit known as petrol engines and those
using heavier liquid fuels, known as oil, compression ignition or
diesel engines.
The important applications of I.C. engines are: (i) Road vehicles,
locomotives, ships and aircraft, (ii) Portable standby units for
power generation in case of scarcity of electric power, (iii)
Extensively used in farm tractors, lawn movers, concrete mixing
devices and motor boats.
12. Classification of I.C. Engines
The internal combustion engines may be classified in the
following ways:
1. According to the type of fuel used
a) Petrol engines, b) Diesel engines, and c) Gas engines.
2. According to the method of igniting the fuel
a) Spark ignition engines, and b) Compression ignition
engines.
3. According to the number of strokes per cycle
a) Four stroke cycle engines, and b) Two stroke cycle
engines.
4. According to the cycle of operation
a) Otto cycle engines, b) Diesel cycle engines, and c) Dual
cycle engines.
13. Classification of I.C. Engines
5. According to the speed of the engine
a) Slow speed engines, b) Medium speed engines, and
c) High speed engines.
6. According to the cooling system
a) Air-cooled engines, and b) Water-cooled engines.
7. According to the method of fuel injection
a) Carburettor engines, and b) Air injection engines.
8. According to the number of cylinders
a) Single cylinder engines, and b) Multi-cylinder engines.
14. Classification of I.C. Engines
9. According to the arrangement of cylinders
a) Vertical engines, b) Horizontal engines, c) Radial engines,
d) In-line multi-cylinder engines, e) V-type multi-cylinder
engines,
f) Opposite-cylinder engines, and g) Opposite-piston engines.
10. According to the valve mechanism
a) Overhead valve engines, and b) Side valve engines.
11. According to the method of governing
a) Hit and miss governed engines, b) Quantitatively
governed engines, and Qualitatively governed engines.
15. Basic Idea of I.C. Engines
The basic idea of internal combustion engine is shown in Fig.
(Basic idea of I.C. engine). The cylinder which is closed at one
end is filled with a mixture of fuel and air. As the crankshaft
turns it pushes cylinder. The piston is forced up and compresses
the mixture in the top of the cylinder. The mixture is set alight
and, as it burns, it creates a gas pressure on the piston, forcing it
down the cylinder.
This motion is shown by arrow ‘1’. The piston pushes on the rod
which pushes on the crank. The crank is given rotary (turning)
motion as shown by the arrow ‘2’. The flywheel fitted on the end
of the crankshaft stroes energy and keeps the crank turning
steadily.
17. Constructional details of I.C. Engines
A cross-section of an air-cooled I.C. engine with principal parts
is shown in Fig. (Air-cooled I.C. engine).
A. Parts common to both Petrol and Diesel engine:
1. Cylinder,
2. Cylinder head,
3. Piston,
4. Piston rings, 5. Gudgeon pin,
6. Connecting rod,
7. Crankshaft,
8. Crank,
9. Engine bearing,
10. Crank case. 11. Flywheel,
12. Governor,
13. Valves and valve operating mechanism.
B. Parts for Petrol engines only:
1. Spark plug,
2. Carburettor,
3. Fuel pump.
C. Parts for Diesel engine only :
1. Fuel pump,
2. Injector.
19. Constructional details of I.C. Engines
The details of the I.C. Engine parts are:
1. Cylinder - It is one of the most important part of the engine, in
which the piston moves to and fro in order to develop power. The
engine cylinder has to withstand a high pressure (more than 50
bar) and temperature (more than 2000 deg C). Thus the material
for the engine cylinder should be such that it can retain sufficient
strength at such a high pressure and temperature. For ordinary
engines, the cylinder is made of ordinary cast iron. But for heavy
duty engines, it is made of steel alloys or aluminum alloys.
Sometimes, a liner or sleeve is inserted into the cylinder, which
can be replaced when worn out. As the material required for liner
is comparatively small, it cab be made of alloy cast iron having
long life and sufficient resistance to rapid wear and tear to the
fast moving reciprocating parts.
20. Constructional details ofon one Enginescylinder, and act
2. Cylinder head - It is fitted I.C. end of the
as a cover to close the cylinder bore. Generally, the cylinder
head contains inlet and exit valves for admitting fresh charge
and exhausting the burnt gases. In petrol engines, the cylinder
head also contains a spark plug for igniting the fuel-air mixture,
towards the end of compression stroke. But in diesel engines,
the cylinder head contain nozzles, (i.e. fuel valve) for injecting
the fuel into the cylinder.
The cylinder head is cast as one piece and bolted to one end of
the cylinder. The cylinder block and cylinder head are made from
the same material. A copper or asbestos gasket is provided
between the engine cylinder and cylinder head to make an airtight joint.
21. Constructionalconsideredof I.C. Engines (contd..) whose
3. Piston – It is details as the heart of an I.C. engine,
main function is to transmit the force exerted by the burning of
charge to the connecting rod. The piston are generally made of
aluminium alloys which are light in weight. They have good heat
conducting property and also greater strength at higher
temperature.
4. Piston rings – These are circular rings and made of special
steel alloys which retain elastic properties even at high
temperatures. The piston rings are housed in the circumferential
grooves provided on the outer surface of the piston. Generally,
there are two sets of rings mounted for the piston. The function
of the upper rings is to provide air tight seal to prevent leakage
of the burnt gases into the lower portion. Similarly, the function
of the lower rings is to provide effective seal to prevent leakage
of the oil into the engine cylinder.
22. Constructional details of I.C. Engines
5. Connecting rod – It is a link between the piston and
crankshaft, whose main function is to transmit force from the
piston to the crankshaft. Moreover, it converts reciprocating
motion of the piston into circular motion of the crankshaft, in the
working stroke. The upper (i.e. smaller) end of the connecting
rod is fitted to the piston and the lower (i.e. bigger) end of the
crank.
The special steel alloys or aluminium alloys are used for the
manufacture of connecting rods. A special care is required for
the design and manufacture of connecting rod, as it is subjected
to alternatively compressive and tensile stresses as well as
bending stresses.
23. Constructional – It is considered Engines
6. Crankshaft details of I.C. as the backbone of an I.C.
engine whose function is to covert the reciprocating motion of
the piston into the rotary motion with the help of connecting rod.
This shaft contains one or more eccentric portions called cranks.
This part of the crank, to which bigger end of the connecting rod
is fitted, is called crank pin. Special steel alloys are used for the
manufacture of crankshaft. A special care is required for the
design and manufacture of crankshaft
7. Crank case – It is a cast iron case, which holds the cylinder
and crankshaft of an I.C. engine. It also serves as a sump for the
lubricating oil. The lower portion of the crank case is known as
bed plate, which is fixed with the help of bolts.
8. Flywheel – It is a big wheel, mounted on the crankshaft,
whose function is to maintain its speed constant. It is done by
storing excess energy during power stroke, which, is returned
during other stroke.
24. Terms relating to I.C. engines are elaborated in Fig.
I.C. Engines
The various terms relating to
1. Bore – The inside diameter of the cylinder is called bore.
2. Stroke – As the piston reciprocates inside the engine cylinder,
it has got limiting upper and lower positions beyond which it
cannot move and reversal of motion takes place at these limiting
positions. The linear distance along the cylinder axis between
two limiting positions, is called stroke.
3. Top Dead Centre (T.D.C.) – The top most position towards
cover end side of the cylinder is called “top dead centre”. In case
of horizontal engines, this is known as inner dead centre.
4. Bottom Dead Centre – The lowest position of the piston
towards the crank end side of the cylinder is called “bottom dead
centre”. In case of horizontal engines it is called outer dead
centre.
26. Terms relating to I.C. Engines
5. Clearance volume – The volume contained in the cylinder
above the top of the piston, when the piston is at top dead
centre, is called the clearance volume.
6. Swept volume – The volume swept through by the piston in
moving between top dead centre and bottom dead centre, is
called swept volume or piston displacement. Thus, when piston
is at bottom dead centre,
Total volume = swept volume + clearance volume.
27. Sequence of Operation
The sequence of operation in a cycle are as follows:
1. Suction stroke – In this stroke, the fuel vapour in correct
proportion, is applied to the engine cylinder.
2. Compression stroke –. In this stroke, the fuel vapour is
compressed in the engine cylinder.
3. Expansion stroke – In this stroke, the fuel vapour is fired just
before the compression is complete. It results in the sudden rise
of pressure, due to expansion of the combustion products in the
engine cylinder. This sudden rise of pressure pushes the piston
with a great force, and rotates the crankshaft. The crankshaft, in
turn, drives the machine connected to it.
4. Exhaust stroke – In this stroke, the burnt gases (or
combustion products) are exhausted from the engine cylinder,
so as to make space available for the fresh fuel vapour.
28. Four-stroke Cycle
In a four-stroke engine, the working cycle is completed in four
strokes of the piston or two revolutions of the crankshaft. This is
achieved by carrying out suction, compression, expansion and
exhaust processes in each stroke.
29. Comparison of Two-stroke and Four-stroke Cycle
Engine
Following are the advantages and disadvantages of two-stroke
cycle engines over four-stroke cycle engines:
Advantages
1. A two stroke cycle engine gives twice the number of power
strokes than the four stroke cycle engine at the same engine
speed.
2. For the same power developed, a two-stroke cycle engine is
lighter, less bulky and occupies less floor area.
3. As the number of working strokes in a two-stroke cycle
engine are twice than the four-stroke cycle engine, so the turning
moment of a two-stroke cycle engine is more uniform. Thus it
makes a two-stroke cycle engine to have a lighter flywheel and
foundations. This also leads to a higher mechanical efficiency of
a two-stroke cycle engine.
30. Comparison of Two-stroke and Four-stroke Cycle
Engine (contd..) of a two-stroke cycle engine is considerably
4. The initial cost
less than a four-stroke cycle engine.
5. The mechanism of a two-stroke cycle engine is much simpler
than a four-stroke cycle engine.
6. The two-stroke cycle engines are much easier to start.
Disadvantages
1. Thermal efficiency of a two-stroke cycle engine is less than
that a four-stroke cycle engine.
31. Comparison of Two-stroke and Four-stroke Cycle
Engine (contd..)
2. Overall efficiency of a two-stroke cycle engine is also less
than that of a four-stroke cycle engine because in a two-stroke
cycle, inlet and exhaust ports remain open simultaneously for
sometime. A small quantity of charge is lost from the engine
cylinder.
3. In case of a two-stroke cycle engine, the number of power
strokes are twice as those of a four-stroke cycle engine. Thus the
capacity of the cooling system must be higher. There is a greater
wear and tear in a two-stroke cycle engine.
4. The consumption of lubricating oil is large in a two-stroke
cycle engine because of high operating temperature.
5. The exhaust gases in a two-stroke cycle engine creates noise,
because of short time available for their exhaust.
32. Four-stroke Cycle Diesel Engine
It is also known as compression ignition engine because the
ignition takes place due to the heat produced in the engine
cylinder at the end of compression stroke. The four strokes of a
diesel engine sucking pure air are described below:
1. Suction stroke – In this stroke, the inlet valve opens and pure
air is sucked into the cylinder as the piston moves downwards
from the TDC. It continues till the piston reaches its BDC as
shown in Fig.
2. Compression stroke – In this stroke, both the valves are
closed and the air is compressed as the piston move upwards
from BDC to TDC. As a result of compression, pressure and
temperature of the air increases considerably. This completes
one revolution of the crank shaft. The compression stroke is
shown in Fig.
34. Basic terms used in derivation
of efficiency of Otto cycle:Total Cylinder Volume:It is the total volume (maximum volume) of the cylinder in which Otto cycle takes place. In
Otto cycle,
Total cylinder volume = V1 = V4 = Vc + Vs
(Refer p-V diagram above)
where,
Vc → Clearance Volume
Vs → Stroke Volume
Clearance Volume (Vc):At the end of the compression stroke, the piston approaches the Top Dead Center (TDC)
position. The minimum volume of the space inside the cylinder, at the end of the compression
stroke, is called clearance volume (V c). In Otto cycle,
Clearance Volume, Vc = V2
(See p-V diagram above)
Stroke Volume Or Swept Volume (Vs):In Otto cycle, stroke volume is the difference between total cylinder volume and
clearance volume.
Stroke Volume, Vs = Total Cylinder Volume – Clearance Volume = V1 – V2 = V4 – V3
35. Compression Ratio:Compression ratio (r) is the ratio of total cylinder volume to the clearance volume.
Now that we know the basic terms, let us derive expressions for T 2 and T3. These
expressions will be useful for us to derive the expression for air-standard efficiency of
otto cycle. For finding T2, we take process 1-2 and for finding T 3, we take process 3-4.
Process 1-2:
This process is an isentropic (reversible adiabatic) process. For this process, the
relation between T and V is as follows:
36. Process 3-4:This is also an isentropic process. The relation between T and V in this process is similar to
the relation between T and V in process 1-2:
Here,
Efficiency of Otto cycle:It is defined as the ratio between work done during Otto cycle to the heat supplied during
Otto cycle.
Air-Standard Efficiency (thermal efficiency) of Otto cycle,
th
th
37.
38. Stroke 1
(intake) only
air enters
cylinder.
Stroke 2
(compression) air is
compressed to high
extent, raising its
temperature.
Stroke 3 (power)
diesel is injected,high
air temperature
ignites diesel.
Stroke 4
(exhaust) burnt
gases are expelled
from the engine.
39. Diesel Engine Operation
A Diesel engines operation sequence is as follows:
Stroke 1 (intake) – only air enters cylinder.
Stroke 2 (compression) – air is compressed to high
extent, raising temperature.
Stroke 3 (power) – diesel is injected, high air
temperature ignites diesel.
Stroke 4 (exhaust) – burnt gases are expelled from
the engine.
42. Comparison of Petrol and Diesel Engines
Petrol Engines
1.
2.
3.
4.
A petrol engine draws a mixture
of petrol and air during suction
stroke.
The carburettor is employed to
mix air and petrol in the required
proportion and to supply it to the
engine during suction stroke.
Pressure at the end of
compression is about 10 bar.
The charge (i.e. petrol and air
mixture) is ignited with the help
of spark plug.
Diesel Engines
A diesel engine draws only air
during suction stroke.
The injector or atomiser is
employed to inject the fuel at the
end of combustion stroke.
Pressure at the end of
compression is about 35 bar.
The fuel is injected in the form of
fine spray. The temperature of the
compressed air is sufficiently high
to ignite the fuel.
43. Comparison of Petrol and Diesel Engines
5.
6.
7.
8.
9.
The combustion of the fuel takes
place at constant volume. It
works on Otto cycle.
A petrol engine has compression
ratio from 6 to 10.
The starting is easy due to low
compression ratio.
As the compression ratio is low,
the petrol engines are lighter and
cheaper.
The running cost of a petrol
engine is high because of the
higher cost of petrol.
The combustion of the fuel takes place
at constant pressure. It works on
Diesel cycle.
A diesel engine has compression
ratio from 15 to 25.
The starting is difficult due to high
compression ratio.
As the compression ratio is high,
the diesel engines are heavier and
costlier.
The running cost of diesel engine is
low because of the lower cost of
diesel.
44. Comparison of Petrol and Diesel Engines
10.
11.
12.
13.
14.
The maintenance cost is less.
The thermal efficiency is about
26%.
Overheating trouble is more due
to low thermal efficiency.
These are high speed engines.
The petrol engines are generally
employed in light duty vehicle
such as scooters, motorcycles
and cars. These are also used in
aeroplanes.
The maintenance cost is more.
The thermal efficiency is about
40%.
Overheating trouble is less due to
high thermal efficiency.
These are relatively low speed
engines.
The diesel engines are generally
employed in heavy duty vehicles
like buses, trucks, and earth
moving machines.