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ENGINES
IC ENGINE
HEAT ENGINE CLASSIFICATION:
HEAT ENGINE
IC ENGINE EC ENGINE
FOUR
STROKE
TWO
STROKE
IC ENGINE
An Internal Combustion Engine is a heat
engine in which the ignition and
combustion takes place within the engine
IC ENGINE CLASSIFICATION:
IC ENGINE
FOUR STROKE
ENGINE
TWO STROKE
ENGINE
A 4-stroke engine goes through four
strokes, or two complete revolutions,
to complete one power output.
A 2-stroke engine goes through
2 strokes, or one complete
revolution, to complete one
power output.
Based on the number of strokes per cycle IC engine
is classified as follows
FOUR STROKE
ENGINE:
The four stroke process includes:
Intake stroke : The intake valve is open,
and fuel is drawn in with a downward
stroke.
Compression stroke : As the piston
moves upward, the fuel is compressed.
Power stroke : After the fuel is
compressed, it is ignited to produce the
engine’s power.
Exhaust stroke : The exhaust valve
WORKING:
The two stroke process includes:
Upstroke (compression/ignition): The
piston goes up, air and fuel enter
the crankcase. The fuel-air mixture
is compressed and ignited.
Downstroke (power/exhaust): Once
the fuel is ignited, the piston is
pushed down, and the exhaust is
expelled.
TWO STROKE
ENGINE:
WORKING:
INTAKE AND EXHAUST PORT:
•The openings in 4 stroke engine are opened
and closed by inlet and exhaust valves, which
are operated by a special system called
camshaft
•The openings in 2 stroke engine, which are
called as ports, are opened and closed by the
movement of the piston only and do not have
any special system
•4-stroke engines have a separate oil system
for lubrication which allows for more
precise lubrication and better protection of
engine components.
•2-stroke engines require oil to be mixed with
the fuel to lubricate the engine
components.
LUBRICATION:
The thermal efficiency of a heat engine is the
percentage of heat energy that is transformed
into work
•Four-stroke engines have more time to
complete the combustion process, which
results in a more complete combustion and
better thermal efficiency
THERMAL EFFICIENCY:
•Two-stroke engines have less time to complete
the combustion process, and their design results
in more fuel loss and less efficient fuel
combustion.
Thus four stroke engine provides better mileage
than two stroke engines
Two-stroke engines produce power every
time the piston completes a cycle, which
occurs twice as often as in a four-stroke
engine. This means that for the same
displacement and cylinder size, a two-stroke
engine can produce more power output than
a four-stroke engine.
POWER OUTPUT:
•Four stroke engine requires heavier flywheel because of
non uniform torque of crankshaft
•Two stroke engine requires lighter flywheel because of
uniform torque
FLYWHEEL:
Four-stroke engines are more
complex than two-stroke engines, with
more moving parts and components.
COMPLEXITY:
• 2-stroke engines are typically lighter and
more compact than 4-stroke engines due to
their simpler design. This makes them well-
suited for applications where weight and size
are important considerations, such as in
handheld power tools and small watercraft.
WEIGHT AND SIZE:
• 2-stroke engine has a more frequent and
intense combustion process, which can
lead to increased wear and tear on the
engine components.
• The oil in a 2-stroke engine can break
down and accumulate over time, leading
to carbon buildup and increased wear on
the engine components.
WEAR AND TEAR:
• 2-stroke engines have a simpler design than 4-stroke
engines, which means that they have fewer
components to distribute the load and absorb the
shock of the engine operation. This can result in
increased wear and tear on the engine components.
•Four stroke engines require maintenance, due
to their more complex design and additional
components such as camshafts, valves, and
timing belts.
•Two stroke engines require maintenance , as
the oil in the fuel mixture can cause carbon
buildup and other issues.
MAINTENANCE:
•2-stroke engines produce higher emissions
4-stroke engines due to their less efficient
combustion process. 2-stroke engines burn a
mixture of fuel and oil, which results in higher
emissions of unburned hydrocarbons and
particulate matter and they causes high
pollution.
EMISSIONS:
•Four-stroke engines are generally more
expensive to produce and maintain than two-
stroke engines, due to their higher complexity
and additional components .
•However, two-stroke engines tend to be less
fuel-efficient than four-stroke engines. This
means that over time, the cost of operating a
two-stroke engine may be higher than that of a
four-stroke engine, as more fuel will be required
to achieve the same amount of power output.
COST:
•Advantages of four-stroke engines include their
superior fuel efficiency, cleaner emissions, and
longer lifespan compared to two-stroke engines.
They are also quieter and produce less vibration,
making them more suitable for larger and more
complex machinery.
•Advantages of two-stroke engines include their
simple design, low cost, and high power-to-weight
ratio. They are also more efficient than four-stroke
engines at high speeds, making them popular for
ADVANTAGES:
Four stroke
engine:
• The cycle is completed in 4
strokes of piston or two
revolution of crank shaft.
• Four stroke engine contains
valves and valve mechanism.
• Complicated lubrication system.
Two stroke
engine:
• The cycle is completed in 2 strokes
of piston or one revolution of crank
shaft
• Two stroke engine contains ports
and port mechanism
•Simple lubrication system
DIFFERENCE BETWEEN FOUR AND
TWO STROKE ENGINE:
• Engine is cooled by water
• Thermal efficiency is high.
• Power output is low.
• Heavier flywheel is required
because of non- uniform torque on
the crank shaft
• These are more complex compared
to 2-stroke engines.
• These engines are heavier due to
heavy flyweel and valve
mechanism
• Engine is cooled by air .
• Thermal efficiency is low
• Power output is high
• Lighter flywheel is enough
because of uniform torque.
• These are more simpler in
structure compared to 4-stroke
engine.
• These engines are lighter due to
its simple structure
• Less wear and tear occurs.
• These engines require more
maintenance.
• These engines produce less
smoke.
• These are more costly to
manufacture due to more moving
parts.
• Used in heavy vehicles.
Eg: car, buses, aeroplanes, etc.,
• More wear and tear occurs
due to poor lubrication.
• These engines require less
maintenance.
• These engines produce
more smoke .
• These are more cheaper to
manufacture.
• Used in light vehicles.
Eg: scooter, motor cycle, etc.,
THANK
YOU

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IC Engine Types: 4-Stroke vs 2-Stroke Comparison

  • 2. HEAT ENGINE CLASSIFICATION: HEAT ENGINE IC ENGINE EC ENGINE FOUR STROKE TWO STROKE
  • 3. IC ENGINE An Internal Combustion Engine is a heat engine in which the ignition and combustion takes place within the engine
  • 4. IC ENGINE CLASSIFICATION: IC ENGINE FOUR STROKE ENGINE TWO STROKE ENGINE A 4-stroke engine goes through four strokes, or two complete revolutions, to complete one power output. A 2-stroke engine goes through 2 strokes, or one complete revolution, to complete one power output. Based on the number of strokes per cycle IC engine is classified as follows
  • 5. FOUR STROKE ENGINE: The four stroke process includes: Intake stroke : The intake valve is open, and fuel is drawn in with a downward stroke. Compression stroke : As the piston moves upward, the fuel is compressed. Power stroke : After the fuel is compressed, it is ignited to produce the engine’s power. Exhaust stroke : The exhaust valve WORKING:
  • 6. The two stroke process includes: Upstroke (compression/ignition): The piston goes up, air and fuel enter the crankcase. The fuel-air mixture is compressed and ignited. Downstroke (power/exhaust): Once the fuel is ignited, the piston is pushed down, and the exhaust is expelled. TWO STROKE ENGINE: WORKING:
  • 7. INTAKE AND EXHAUST PORT: •The openings in 4 stroke engine are opened and closed by inlet and exhaust valves, which are operated by a special system called camshaft •The openings in 2 stroke engine, which are called as ports, are opened and closed by the movement of the piston only and do not have any special system
  • 8. •4-stroke engines have a separate oil system for lubrication which allows for more precise lubrication and better protection of engine components. •2-stroke engines require oil to be mixed with the fuel to lubricate the engine components. LUBRICATION:
  • 9. The thermal efficiency of a heat engine is the percentage of heat energy that is transformed into work •Four-stroke engines have more time to complete the combustion process, which results in a more complete combustion and better thermal efficiency THERMAL EFFICIENCY:
  • 10. •Two-stroke engines have less time to complete the combustion process, and their design results in more fuel loss and less efficient fuel combustion. Thus four stroke engine provides better mileage than two stroke engines
  • 11. Two-stroke engines produce power every time the piston completes a cycle, which occurs twice as often as in a four-stroke engine. This means that for the same displacement and cylinder size, a two-stroke engine can produce more power output than a four-stroke engine. POWER OUTPUT:
  • 12. •Four stroke engine requires heavier flywheel because of non uniform torque of crankshaft •Two stroke engine requires lighter flywheel because of uniform torque FLYWHEEL:
  • 13. Four-stroke engines are more complex than two-stroke engines, with more moving parts and components. COMPLEXITY:
  • 14. • 2-stroke engines are typically lighter and more compact than 4-stroke engines due to their simpler design. This makes them well- suited for applications where weight and size are important considerations, such as in handheld power tools and small watercraft. WEIGHT AND SIZE:
  • 15. • 2-stroke engine has a more frequent and intense combustion process, which can lead to increased wear and tear on the engine components. • The oil in a 2-stroke engine can break down and accumulate over time, leading to carbon buildup and increased wear on the engine components. WEAR AND TEAR:
  • 16. • 2-stroke engines have a simpler design than 4-stroke engines, which means that they have fewer components to distribute the load and absorb the shock of the engine operation. This can result in increased wear and tear on the engine components.
  • 17. •Four stroke engines require maintenance, due to their more complex design and additional components such as camshafts, valves, and timing belts. •Two stroke engines require maintenance , as the oil in the fuel mixture can cause carbon buildup and other issues. MAINTENANCE:
  • 18. •2-stroke engines produce higher emissions 4-stroke engines due to their less efficient combustion process. 2-stroke engines burn a mixture of fuel and oil, which results in higher emissions of unburned hydrocarbons and particulate matter and they causes high pollution. EMISSIONS:
  • 19. •Four-stroke engines are generally more expensive to produce and maintain than two- stroke engines, due to their higher complexity and additional components . •However, two-stroke engines tend to be less fuel-efficient than four-stroke engines. This means that over time, the cost of operating a two-stroke engine may be higher than that of a four-stroke engine, as more fuel will be required to achieve the same amount of power output. COST:
  • 20. •Advantages of four-stroke engines include their superior fuel efficiency, cleaner emissions, and longer lifespan compared to two-stroke engines. They are also quieter and produce less vibration, making them more suitable for larger and more complex machinery. •Advantages of two-stroke engines include their simple design, low cost, and high power-to-weight ratio. They are also more efficient than four-stroke engines at high speeds, making them popular for ADVANTAGES:
  • 21. Four stroke engine: • The cycle is completed in 4 strokes of piston or two revolution of crank shaft. • Four stroke engine contains valves and valve mechanism. • Complicated lubrication system. Two stroke engine: • The cycle is completed in 2 strokes of piston or one revolution of crank shaft • Two stroke engine contains ports and port mechanism •Simple lubrication system DIFFERENCE BETWEEN FOUR AND TWO STROKE ENGINE:
  • 22. • Engine is cooled by water • Thermal efficiency is high. • Power output is low. • Heavier flywheel is required because of non- uniform torque on the crank shaft • These are more complex compared to 2-stroke engines. • These engines are heavier due to heavy flyweel and valve mechanism • Engine is cooled by air . • Thermal efficiency is low • Power output is high • Lighter flywheel is enough because of uniform torque. • These are more simpler in structure compared to 4-stroke engine. • These engines are lighter due to its simple structure
  • 23. • Less wear and tear occurs. • These engines require more maintenance. • These engines produce less smoke. • These are more costly to manufacture due to more moving parts. • Used in heavy vehicles. Eg: car, buses, aeroplanes, etc., • More wear and tear occurs due to poor lubrication. • These engines require less maintenance. • These engines produce more smoke . • These are more cheaper to manufacture. • Used in light vehicles. Eg: scooter, motor cycle, etc.,