Side-Feed – Fuel enters on the side on the injector fitting inside the fuel rail.ģ. Top-Feed – Fuel enters from the in the top and exits the bottom.Ģ. feed pump – sucks fuel from the fuel tankġ.injection nozzle - injects the fuel into the cylinder.high-pressure pipe - sends fuel to the injection nozzle.fuel injection pump - pressurizes fuel to high pressure.At the same time, it must maintain the required air-fuel ratio as per the load and speed demand on the engine. The objectives of the fuel injection system are to meter, atomize and distribute the fuel throughout the air mass in the cylinder. When fuel is pressurized by the injection pump and then atomized from the injection nozzle, it mixes thoroughly with air, thus improving ignition. As this period of time is almost constant, irrespective of engine speed, a timer is used to adjust and change injection timing – enabling optimum combustion to be achieved. Ignition delay is the period of time between the point when the fuel is injected, ignited and combusted and when maximum combustion pressure is reached. Since the engine output is almost proportional to the injection quantity, this is adjusted by the accelerator pedal. If the injection quantity is changed with the engine speed and the injection timing is constant, the output and fuel consumption change. In diesel engines the intake of air is almost constant, irrespective of the rotating speed and load. The fuel is compressed to high pressure when the cam lifts the plunger, and is then sent to the injector. Pump elements such as the cylinder and plunger are built into the injection pump body. The diesel fuel injection system has four main functions: 1. When ECU determined the exact amount of fuel and when to inject it, activates the appropriate injector by switching the other terminal to the ground (mass, i.e. The one terminal of the injector coil is directly supplied by 12 volts which are controlled by the ECU, and the other terminal of the injector coil is open. In that way opens the injector and allows petrol to pass through it into the engine. So, the ECU sends a command electrical signal of the correct duration and timing to the fuel injector coil. The electronic control unit (ECU at engine management system) determines the precise amount and specific timing of required gasoline (petrol) dose for every cycle, by collecting information from various engine sensors. By pressurizing and injecting the fuel, the system forces it into air that has been compressed to high pressure in the combustion chamber.įuel injector is an electronically controlled mechanical device that is responsible for spraying (injecting) the right amount of fuel into the engine so that a suitable air/fuel mixture is created for optimal combustion. The fuel injection system lies at the very heart of the diesel engine. Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector.
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