copy of carburettion & injection

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Engine Fuel System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Petrol Engines

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Fuel/Air ratioThe purpose of the carburettor in case of Petrol Engines is to mix air and fuel, So the fuel/air ratio is theoretically 1:14,6. When the supply of airis more, the ratio gets higher than 1:14,6 i.e. a leaner mixture, there still will be some free oxygen left in the exhaust gases. If the supply of fuel is more than air the ratio gets below 1:14 i.e. a richer mixture,there will be no free oxygen left but some fuel will leave the engine unused.

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Carburettor

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Venturi-type Carburetor

P+1/2 V2 = Constant

Bernoulli Effect:

Constant level is maintained in bowl -as float moves down, valve stem moves down, allowing more fuel into bowl, float moves up and closes valve

Valve StemFuel Inlet

Float

Metering Orifice

Throttle Plate

Air/Fuel Mixture To Engine

Choke Plate

Fuel Nozzle

Inlet Air

Bowl

Atomized Fuel

Venturi

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Desirable Features

1 To meter & supply the correct amount of air fuel mixture ratios under all conditions of load & speed of the engine for

• Easily Starting

• Providing rich mixture forslow idling

• Providing rich mixture for aceleration

• Providing rich mixture for high speed

2 To operate satisfactorily during hot & cold weathers

3 To be robust

4 To withstand the density changes for varying altitudes.

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Main Systems

• Float System

• Idle System

• Main Metering System

• Power System

• Accelerator Pump System

• Choke System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Float System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Idle System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Low Speed Operation

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Main Metering System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Metering Rod Types

• Tapered

• Stepped

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Tapered Rod

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Stepped Rod

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Power System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Accelerator Pump System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Choke System

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Diesel Fuel System

In diesel fuel system only air is sucked into the cylinder during the intake stroke.

The combustion of fuel takes place as soon as the diesel is injected into the cylinder prior to power stroke.

CARBURETION & INJECTION Copyright Gautam Malik 2007C

CARBURETION & INJECTION Copyright Gautam Malik 2007C

The injection in case of diesel engine is executed with the help of Fuel Injection Pump(FIP)in conjunction to the nozzles /injectors.

The Main parts of the FIP are

• FIP driving gear

• FIP Cam Shaft

• Followers

• Plungers

• Barrels

• Retaining Springs

• Governor

• Spring Loaded rack arrangement

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Main Parts

CARBURETION & INJECTION Copyright Gautam Malik 2007C

No Delivery

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Full Delivery

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Partial Delivery

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Barrel

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Mechanical Injectors

CARBURETION & INJECTION Copyright Gautam Malik 2007C

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Nozzle

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Fuel Injection

CARBURETION & INJECTION Copyright Gautam Malik 2007C

Multi Point Fuel Injection(MPFI)

50 psi typical

Monitored Engine Operating Conditions:

Manifold PressureEngine Speed

Air TemperatureCoolant Temperature

Acceleration

COMPUTERTRIGGER

INJECTOR DRIVE UNIT

Pressure Regulator FuelFilter

Fuel Pump

FUEL TANK

Injectors

CARBURETION & INJECTION Copyright Gautam Malik 2007C

THANK YOU