What's the difference between a 2-stroke engine and a 4-stroke engine?

WHAT'S THE DIFFERENCE BETWEEN A
2-STROKE ENGINE AND A 4-STROKE ENGINE?

 

S.No.	Four stroke engine	Two stroke engine
1.	It has one power stroke for every two revolutions of the crankshaft.	It has one power stroke for each revolution of the crankshaft.
2.	Heavy flywheel is required and engine runs unbalanced because turning moment on the crankshaft is not even due to one power stroke for every two revolutions of the crankshaft.	Lighter flywheel is required and engine runs balanced because turning moment is more even due to one power stroke for each revolution of the crankshaft.
3.	Engine is heavy	Engine is light
4.	Engine design is complicated due to valve mechanism.	Engine design is simple due to absence of valve mechanism.
5.	More cost.	Less cost than 4 stroke.
6.	Less mechanical efficiency due to more friction on many parts.	More mechanical efficiency due to less friction on a few parts.
7.	More output due to full fresh charge intake and full burnt gases exhaust.	Less output due to mixing of fresh charge with the hot burnt gases.
8.	Engine runs cooler.	Engine runs hotter.
9.	Engine is water cooled.	Engine is air cooled.
10.	Less fuel consumption and complete burning of fuel.	More fuel consumption and fresh charge is mixed with exhaust gases.
11.	Engine requires more space.	Engine requires less space.
12.	Complicated lubricating system.	Simple lubricating system.
13.	Less noise is created by engine.	More noise is created by engine.
14.	Engine consists of inlet and exhaust valve.	Engine consists of inlet and exhaust ports.
15.	More thermal efficiency.	Less thermal efficiency.
16.	It consumes less lubricating oil.	It consumes more lubricating oil.
17.	Less wear and tear of moving parts.	More wear and tear of moving parts.
18.	Used in cars, buses, trucks etc.	Used in mopeds, scooters, motorcycles etc.

WORKING OF 2-STROKE AND 4-STROKE ENGINE!!!

WORKING OF 2-STROKE AND 4-STROKE ENGINES

Gasoline and diesel engines are both available in either 2-stroke or 4-stroke versions.

In a 4-stroke engine the sequence can be written:

 1.Compression Stroke.

            The piston goes up and compresses a fuel/air mixture (in a gas engine) or just air (in a diesel engine).

2.Power Stroke.

            The fuel is ignited (by a spark in a gas engine, by being injected into high temperature air in a diesel engine). The energy released drives the piston down. This provides the momentum necessary to keep the crankshaft turning and make the other three strokes happen.

3.Exhaust Stroke.

             The piston goes up and pushes the burned gases out the exhaust valve.

4.Intake Stroke.

            The piston goes down and draws in new air, or fuel/air mixture, ready for the next compression stroke.

In a 2-stroke engine, the last three strokes are combined into one.

1.Compression Stroke.  

           The piston goes up and compresses a fuel/air mixture (in a gas engine) or just air (in a diesel.)

2.Power Stroke.

             The fuel is ignited and drives the piston down. As the piston goes down it not only turns the crankshaft but also pressurizes the fuel/air mixture in the crankcase which is about to be admitted to the piston for the next cycle. Near the bottom of the stroke, an outlet opens and the exhaust gases are released. Even nearer the bottom of the stroke, an inlet opens and new fuel/air (which was just pressurized by the piston) rushes in ready for compression.

Because a 2-stroke engine gets a power stroke twice as often as a four-stroke engine, it puts out about twice as much power, and makes twice as much noise, as a four-stroke engine of the same size.

The downside is that, because the 2-stroke engine is sloppier about how it expels exhaust and takes in fuel, doing them almost at the same time, it is more polluting. Also, the 2-stroke engine lets fuel into the crankcase, where the piston can pressurize it prior to intake. In order to keep the crankcase lubricated, you have to add expensive lubricants to the fuel, and even so, 2-stroke engines don't last very long.

So 2-stroke engines are used in chainsaws and lawnmowers, where power per weight is important but the engine isn't used for long periods so pollution and engine life are less of a concern. The continuously used engines in cars and trucks are 4-stroke engines.

PULSAR RS200

PULSAR RS200

VEHICLE SUMMARY
Current Status	Officially Launched on March 26
Production	March 2015-present
Type	Sports
Frame	Pressed steel perimeter beam section frame
Exhaust	Single right side exhaust
Shades	Red (with black & white graphics), Yellow (with black & white graphics)
Warranty	2 Years or 30,000 Kms
Handle Bar	Tall two piece handlebar (Clip On Bar)
ENGINE, POWER & TORQUE
Displacement	199.5 cc
Maximum Power	24.2 BHP (24.5 PS) @ 9750 rpm
Maximum Torque	18.6 NM @ 8000 rpm
Engine Description	Single cylinder, 4-stroke, SOHC, 4-valve, Liquid Cooled, Triple Spark, Fi (Fuel Injected)
Cooling	Liquid Cooling
Fuel System	Fuel Injection
Ignition	Independent spark control through ECU
Bore	72 mm
Stroke	49 mm
Number of Cylinders	1
Power-to-weight Ratio	146.7 BHP per tonne
Torque-to-Weight Ratio	112.7 NM per tonne
Specific Output	121.30 BHP per litre
Cylinder Configuration	Vertical
Valve System	SOHC
Fuel Type	Petrol
Rev Limit	11000 rpm
Spark Plugs Per Cylinder	3
TRANSMISSION
Gearbox	6 Speed Constant Mesh
Clutch	Wet Multiplate
Final Drive	Chain
BRAKES
Front Brake	300mm butterfly disc brake
Rear Brake	230mm butterfly disc brake
Anti-lock Braking System (ABS)	Optional
SUSPENSION
Front Suspension	Telescopic with anti friction bush
Rear Suspension	Nitrox mono shock absorber with Canister

WHEELS & TYRES
Front Tyre	100/80-17 52 P tubeless
Rear Tyre	130/70-17 62P tubeless
Front Wheel	17-inch
Rear Wheel	17-inch
Wheel Type	Black Alloy Wheels
Tubeless Tyres	YES
Alloy Wheels	YES
BATTERY
Battery Type	Maintenance Free
ELECTRICALS
Electrical System	12V Full DC
DIMENSIONS, WEIGHT & CAPACITIES
Overall Length	1999 mm
Overall Width	765 mm
Overall Height	1114 mm
Ground Clearance	157 mm
Seat Height	Approx. Seat Height - 805 mm
Wheelbase	1355 mm
Kerb/Wet Weight	165 kg
Fuel Tank Capacity	13 litres
PERFORMANCE & MILEAGE
0-100 kmph	9.5-9.8 secs
Top Speed	140.8 kmph
Mileage (City, approx.)	38 kmpl
Mileage (Highway, approx.)	48 kmpl
Mileage (Combined, approx.)	43 kmpl
Mileage (Certified)	54 kmpl
INSTRUMENT CONSOLE
Speedometer	Digital
Tachometer	Analog
Trip Meter	Digital (Twin)
Odometer	Digital
Coolant Temperature	YES
Clock	Digital
ABS Light	NO
Fuel Gauge	Digital
Low Fuel Warning Light	YES
Service Reminder	YES
Low Oil Indicator	YES
Low Battery Indicator	YES
Engine Check Indicator	YES
Rev-limiter Indicator	YES
Fuel Reserve Indicator	YES
COMFORT & CONVENIENCE
Electric Start	YES
Engine Kill Switch	YES
Pillion Footrest	YES
Pillion Grabrail	YES
Step-up Seat/Split Seat	YES
Pass Light	YES
Stand Alarm	YES
Pillion Backrest	NO
OTHER SPECIFICATIONS
Alloy Triple Clamp	YES
LIGHTING
Head Light	Twin projector headlamps (55w low beam and 65w high beam)
Tail Light	Crystal LED
Turn Signal Light (Front)	Bulb
Turn Signal Light (Rear)	Bulb
LED Lamps	LED DRLs
Projector Head Light	YES