22-12-2012, 11:55 AM
ELECTRONIC FUEL INJECTOR
ELECTRONIC FUEL.pptx (Size: 236.34 KB / Downloads: 78)
introduction
Fuel injector and electronic fuel injector is having same work( for mixing the air with fuel).
Fuel injector is controlled by mechanically but electronic fuel injector is controlled by ECU.
Electronic Fuel Injector is a electrical device which is use for mix the air with fuel in proper quantity and fed to the cylinder (combustion chamber).
How electronic fuel injection pump work:
electronic fuel injection pump works on the some very basic principles.
The electronic fuel injection system can be divided in to three subsystem. these are the fuel delivery system ,air induction system, and electronic control system.
FUEL DELIVERY SYSTEM
The fuel delivery system consists of the fuel tank, fuel pump, fuel filter, fuel delivery pipe, fuel injector, fuel pressure regulator & fuel return pipe.
Fuel is delivered from the tank to the injector by means of an electronic fuel pump. The pump is typically located in or near the fuel tank.
Fuel is maintained at a constant pressure by means of a fuel pressure regulator. any fuel which is not delivered to the intake manifold by the injector return to the tank through a fuel return pipe.
THE AIR INDUCTION SYSTEM
The air induction system consists of the air cleaner, air flow meter, throttle valve, air intake chamber.
When the throttle valve is opened air flow through the air cleaner through the flow meter, past the throttle valve and through a well tuned intake manifold runner to the intake valve.
Air delivered to the engine is a function of driver demand. As the throttle valve is opened further, more air is allowed to enter the engine cylinder.
ELECTRONIC CONTROL SYSTEM
The electronic control system consists of various engine sensors, electronic control unit (ECU), fuel injector assemblies & related wiring.
The ECU determines precisely how much fuel needs to be delivered by the injection by monitoring engine sensors.
The ECU turns the injector on for a precise amount of time, referred to as injection pulse width or injection duration to deliver the proper air fuel ratio to the engine.
BASIC SYSTEM OPERATION
Air enters the engine through the air induction system where it is measured by the air flow meter, as the air flows into the cylinder, fuel is mixed into the air by the fuel injector.
Fuel injector is arranged in the intake manifold behind each intake valve. the injector are electronic solenoids which are operated by the ECU.
When the injector is turned on , it opens spraying atomized fuel at the back side of the intake valve.
As fuel is sprayed in to the intake airstream it mix with the incoming air and vaporizes due to the low pressure in the intake manifold. The ECU signals the injector to deliver just enough fuel to achieve an ideal air/fuel ratio of 14.7:1.
Electronic Control
Unit At the heart of electronic fuel-injection (EFI) systems is the fuel control or electronic-control unit (ECU) with a stored map of operating conditions. Electronic sensors provide data to the microprocessor in the ECU, which calculates and sends the output signals to the system actuators, which are the fuel pump, fuel injectors and idle air-control units. The ECU will also switch some of the exhaust emission and auxiliary system components.