Inter Combustion engine (I.C.Engine)

             Internal combustion engine

It is an engine which converts heat energy into mechanical energy. Heat is produced due to process of combustion

Classification

·       Type of fuel used

a.     Petrol engine

b.    Diesel engine

c.      Bio-fuel engine

·       No of strokes

a.      2 stroke engine

b.      4 stroke engine

Stroke: - linear momentum of piston inside cylinder.

Four strokes are: - ignition, compression, expansion, exhaustion.

·        Method of ignition

a.      Spark ignition engine (also known petrol engine)

--eternal medium like spark from spark plug is given to ignite charge (charge is mixture of petrol and gas.)

b.      Compression ignition engine

--gas is compressed to that much extent so it burst to ignite fuel.

è Petrol ignition engine has more temperature than diesel.

·        According to thermodynamic cycles

a.      Otto cycle (principle for petrol engine.)

Otto cycle: Otto cycle is the typical cycle for most of the cars internal combustion engines that work using gasoline as a fuel

b.      Diesel cycle

·        On method of cooling

a.      Air cooled engine

b.      Water cooled engine

          Petrol engine               

                     

       Working

·        Ignition

                 Petrol engines use spark ignition and high voltage current for the spark may be provided by a magneto or an ignition coil. In modern car engines the ignition timing is managed by an electronic Engine Control Unit.

·       Cooling

                      Petrol engines may be air-cooled, with fins (to increase the surface area on the cylinders and cylinder head); or liquid-cooled, by a water jacket and radiator. The coolant was formerly water, but is now usually a mixture of water and either ethylene glycol or propylene glycol. The cooling system is usually slightly pressurized to further raise the boiling point of the coolant.

·        Power measurement

The most common way of engine rating is what is known as the brake power, measured at the flywheel, and given in kilowatts (metric) or horsepower (USA). The term "brake" comes from the use of a brake in a dynamometer test to load the engine

·       

      Different parts of Internal Combustion Engine

1.      Inlet valve: it is moved with help of rocker arm to lift up and pass the charge or gas.

2.      Piston: it moves up and down between TDC (top dead centre) & BDC (bottom dead centre) to produce a stroke.

7. Crank Shaft: it rotates with every stroke (half with one stroke) and provides power for exhaust, expansion.

9. Outlet valve: it’s also moved with rocker arm to pass the exhaust gas.

10: Piston Ring: it provides sealing action for piston to restrict passage of fuels and gas to crank shaft.

è Bore: it is the internal diameter of cylinder

è Spark plug is used in case of petrol engine and fuel injector is used in case of diesel engine.