Difference between 2 Stroke Engine and 4 Stroke Engine

2 STROKE ENGINE	4 STROKE ENGINE
The cycle is completed in 2 strokes of the piston	The cycle is completed in 4 strokes of the piston
It has one power stroke in 1 cycle of crankshaft	It has one power stroke in 2 cycle of crankshaft
It has ports	It has valves
Smaller flywheel	Bigger flywheel
Greater cooling and lubrication required	Less requirement of cooling and lubrication required
Parts are cheap in cost and for same power  light weight engine is requires	Parts are cheap in cost and for the same power  heavy  weight engine is required
Uniform torque distribution	Non-uniform torque distribution
Less volumetric and thermal efficiency	More volumetric and thermal efficiency
Simple in design	Complex in design
Less in demand	More in demand
Used in lawn movers, scooters, motorcycles, mopeds, etc.	Used in high efficiency motor cycles, cars ,buses, trucks, aeroplanes, power generation, etc.

 

Important terminology of IC engine

BORE(D)

The inside diameter of engine cylinder is known as bore. 
It is measured in mm.
In the bore piston is fitted.

PISTON AREA (A)::-

 The area of circle of diameter equal to the cylinder bore.

STROKE(L):-

When piston is in reciprocating motion, the distance travelled by the piston from one dead centre position to the other dead centre position

DEAD CENTERS:-

Extreme positions within which piston do its reciprocating motion.

1.TOP DEAD CENTER(TDC)-

Top most position of the piston towards the cover end side of the engine.

2.BOTTOM DEAD CENTER(BDC)-

Lower most position of the piston towards the crank end of the engine.

CRANK THROW/CRANK RADIUS:-

The distance between the center of the main shaft and center of the crank-pin is known as crank throw or crank radius.

SWEPT VOLUME(Vs):-

The volume of fluid that can be comprised within the top dead centers and the bottom dead centers.
Vs=A × L

CLEARANCE VOLUME(Vc):-

The volume that can be comprised within top dead center and the head of the cylinder.
Piston never enters this portion of cylinder.

TOTAL CYLINDER VOLUME(V):-

Sum of swept volume and clearance volume
Total cylinder volume = Vs + Vc

COMPRESSION RATIO(r):-

It is the ratio of total cylinder volume to the clearance volume.
r = Vs+Vc/Vc  
compression ratio of Petrol- 5:1 - 9:1
and for                     Diesel- 14:1 - 22:1

DIFFERENCE B/W INTERNAL COMBUSTION(IC ENGINE) AND EXTERNAL COMBUSTION ENGINE(EC ENGINE)

IC Engine(internal combustion engine)	EC Engine(external combustion engine)
Combustion of fuel takes place inside engine cylinder.	Working fluid (steam) is produce in a boiler which is outside the power producing unit.
Higher thermal efficiency (35-40%)	Low thermal efficiency (10-15%)
The product of combustion after doing useful work is exhausted in the atmosphere.	The steam after doing useful work is rejected to a condenser where steam is reused.
Very easy to start as can be started simultaneously.A starting motor is used in automobiles.	First boiler has to be fired, then steam is raised and then steam engines are started.
Have  single acting cylinders	Have double acting cylinders Exception- atmospheric engines & beam engines
Advantages- power to weight ratio high,  Higher thermal efficiency, Less space required, Start instantly.	Advantages- low emission, Low noise and vibration, Potentially long life, Easy availability of fuel, Huge power generation.
Disadvantages – fuel used is very costly,  Exhaust gases are toxic, Not suitable for large scale power generation, An engine produces noises due to detonation or knocking.	Disadvantages- Leakage of working fluid, Size of engine is very big, Overall working temperature is high so Maintenance and spl. Building materials are required, Not suitable for low power requirements

               IC ENGINE                                                        EC ENGINE

   

Everthing about Engine

 

  The Engine is the vehicle’s main source of power. This is where chemical energy is converted into mechanical energy. The most popular type of engine is referred to as the Internal Combustion Engine. This engine burns an air/fuel mixture inside itself in order to drive a series of pistons and connecting rods that in turn rotate a crankshaft providing us with a continuous rotating motion with which to drive the vehicle and other components. The engine also incorporates others systems, including the lubrication system and the cooling system, all working efficiently together. The cooling system maintains the engine at an ideal operating temperature while the lubrication system ensures that all the moving parts are kept well oiled in order to provide a long serviceable life. Converts reciprocating motion of piston to rotatory motion of crankshaft.

 

IC Engines- The  heat engines in which combustion of fuel takes place inside the engine cylinder. Eg- Petrol engine ,Diesel engine, CNG engine,etc.

jet turbine- ROTATORY IC ENGINE

EC Engines- The heat engines in which combustion of fuel takes place outside of the engine cylinder.Eg- Steam engines,Gas turbines,etc.

Sterline engine- reciprocating EC Engine

Reciprocating Engine- In these engines piston movement is reciprocating inside the cylinder and  convert reciprocating motion of piston to rotatory motion of crankshaft.

reciprocating piston and cylinder setup

Rotatory Engine -In there engines pistons reciprocating motion is changed to rotary motion . they make three lobe rotor which rotatees eccentically in an oval shape of chamber or housing. 

wrankle rotary cylinder setup