Carburetor.ppt

CarburetorCarburetor

OutlinesOutlines

Carburetor Carburetor

Working principle of carburetorWorking principle of carburetor

Function and uses of ChokeFunction and uses of Choke

OverflowOverflow

AcceleratorAccelerator

The function of a The function of a carburetor in a vehicle is carburetor in a vehicle is similar to that of a human similar to that of a human

Heart.Heart.

CarburetorCarburetor

To maintain a small reserve of petrol To maintain a small reserve of petrol at constant headat constant head

To vaporize the petrol by means of To vaporize the petrol by means of engine suction and to produce engine suction and to produce homogenous air fuel mixture homogenous air fuel mixture

To supply the required air & petrol at To supply the required air & petrol at the correct mixture strength the correct mixture strength

Fuel

Air

Carburetor

Engine Cylinde

r

Throttle Valve

Inlet Exhaust

Block diagram of Carburetor

Working principle of Working principle of carburetorcarburetor

ChokeChoke

FunctionFunction

To supply very rich To supply very rich mixture so that the mixture so that the ratio of the air to ratio of the air to vaporized fuel in the vaporized fuel in the cylinder is within the cylinder is within the combustible limitcombustible limit

UsesUses

During winter During winter season, it season, it supplies extra supplies extra fuelfuel

Air-fuel mixtureAir-fuel mixture

Too rich to burn

Combustible range Too lean to burn

9:1 19:115:1

Excess Fuel Excess Air

• Chemically correct mixtureChemically correct mixture• Rich mixtureRich mixture• Lean mixtureLean mixture

OverflowOverflow

When the mixture of air and fuel When the mixture of air and fuel becomes more richer than the becomes more richer than the ratio 9:1 then the condition of ratio 9:1 then the condition of OverflowOverflow occurs. occurs.

Reasons of overflowReasons of overflow

When the choke valve remains closed When the choke valve remains closed for a long time. for a long time.

When the float valve needle does not When the float valve needle does not close the intake of petrol in the float close the intake of petrol in the float chamber and the petrol overflows.chamber and the petrol overflows.

When the vehicle remains tilted to When the vehicle remains tilted to one side for a long period.one side for a long period.

How vehicle can be started How vehicle can be started after overflowafter overflow

Open the spark plug , clean it Open the spark plug , clean it and apply kick several times and apply kick several times so that the overflowed petrol so that the overflowed petrol may be expelled out from the may be expelled out from the engine cylinder.engine cylinder.Put the petrol knob at the Put the petrol knob at the Closed condition, open the Closed condition, open the accelerator to its maximum accelerator to its maximum and apply kicks continuously.and apply kicks continuously.

How accelerator worksHow accelerator works

On applying the accelerator, it opens the On applying the accelerator, it opens the throttle valve and the air-fuel mixture starts throttle valve and the air-fuel mixture starts entering into the engine cylinder in the entering into the engine cylinder in the increased amount continuously so that the increased amount continuously so that the engine gets more power to produce its engine gets more power to produce its power strokes and the output of the engine power strokes and the output of the engine increased and hence the speed of the increased and hence the speed of the vehicle. vehicle.

Thank youThank you