MECHANICAL ENGINEER


Engine:-The definition of engine is the machine converting energy  into  mechanical force and motion .get its energy  from a source of a heat such burning a fuel  .using diesel ,petrol,gas.
Engine using -car,bus,track,motors,train,auto rickshaw,generator's etc.




Components/Parts Of the Engines

Cylinder :-As the name implies, it is a cylinder vessel or space
in which the piston makes a reciprocating motion .

Piston:-It is cylindrical component fitted into the cylinder 
forming the moving boundary of the combustion system.

Combustion Chamber:-The space enclosed in the upper parts of the cylinder ,by the cylinder head and the piston top during the combustion process,is called combustion chamber.

Inlet Manifold:-The pipe through which air or air- fuel mixture is drawn into the cynder is called the inlet manifold.

Exhaust Manifold:-The pipe through which the products of combustion escape(exit) into the atmosphere is called the exhaust manifold. 

Spark Plug:-It is a component to initiate the combustion process in spark Ignition (SI) engines.

Crankshaft:-It convert the reciprocating motion of the piston into useful rotary motion of the output shaft.

Piston Rings:-Piston ring fitted into the slots around the piston ,provide a tight seal between the piston and the cylinder wall.

Gudgeon pin:-It form the link between the small end of the connecting rod and the piston.

Camshaft:-The camshaft and its associated parts control the opening and closing of the two valves.

Cams:-These are made as integral parts of camshaft and the designed in such a way to open the valve at the correct timing and to keep them open for the necessary duration.

Flywheel:-The net torque imparted to the crankshaft during one complete cycle of operation of the engine fluctuates causing a change in the angular velocity of the shaft. 

Diesel engine 

1. A diesel engine drawn only air during suction stroke.

2. The injector or atomiser is employed to inject the fuel at the end of compression stroke.

3. The pressure at the end of compression is about 35 bar.

4. The fuel injected in the form of fine spray. The temperature of the compressed air (about 600°C at the pressure about 35 bar) is sufficiently high to ignite the fuel.

5. The combustion of fuel take place approximately at constant pressure. In other word, it work on diesel cycle.

6. A diesel engine has compression ratio approximately from 15 to 25.

7. The starting little difficult due to high compression ratio.

8. Diesel engine maintenance cost is more.

9. The thermal efficiency is up to about 40%.

10.The diesel engines are generally employed in heavy duty vehicles such as bus,track and earth moving machine.

11.These are relatively low speed engine.

12.As the compression ratio is high ,the diesel engine are heavier and costlier.

Petrol Engine

1.A petrol engine draws a mixture of petrol and air during suction stroke.

2.The carburettor is employed to mix air and petrol in the required proportion and to supply it to the engine during suction stroke.

3. The pressure at the end of compression is about 10 bar.

4.The change(i.e.petrol and air mixture) is ignited with the help of a spark plug.

5. The combustion of fuel take place approximately at constant volume. In other word, it work on otto cycle.

6. A diesel engine has compression ratio approximately from 6 to 10.

7. The starting is easy due to low compression ratio.

8.As the compression ratio is low ,the petrol engine are lighter and cheaper.

9.The running cost of petrol engine is high because of higher cost of petrol.

10.The Maintenance cost is less compare diesel engine.

11.The thermal efficiency is upto about 26%.

12. The petrol engine are generally employed  in light duty vehicles such as scooty,  motorbike,car these are also used in aero planes.   

CLUTCH
The basic function of the clutch is to control the the flow of mechanical power within a machine .it must be capable of transmitting specified amount of torsional moment. the clutch is also called upon the convert potential or kinetic energy into internal energy and  to dissipate it in the form of heat ,transfer from the clutch to the atmosphere.The other main functions of a clutch are;



1.To start and stop a machine or rotating element without starting and stopping the prime mover.

2.To maintain constant speed,torsional moment and power.

3.To limit torsional moment.