CARBURETION & INJECTION Copyright Gautam Malik 2007 C Engine Fuel System
Jun 13, 2015
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
CARBURETION & INJECTION Copyright Gautam Malik 2007C
Stepped Rod
CARBURETION & INJECTION Copyright Gautam Malik 2007C
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
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