In my previous post, "How Fuel Is Supplied In Diesel Engine? " you can find brief description about fuel supply methods.In this post,I will cover the important components of fuel injection system of diesel engine.The fuel injection system has contains following important components,
01)Fuel feed Pump
02)Fuel Injection pump
03)Fuel Atomiser and nozzles
Out of above parts,you will come to know in detail about Fuel Feed Pump.
Construction And Working Of Fuel Feed Pump:-
The fuel which is stored in fuel storage tank is taken to injection system through fuel filters.The fuel,either by gravity or by mechanical pressure is supplied to injection system.The fuel start flowing to the injection pump under gravity head as fuel tank is placed at a higher level than engine,in gravitation feed system.this type of arrangement is most suitable for stationary engines.
In mechanical pressure system,the fuel is sucked from the fuel tank by a mechanically operated fuel feed pump and is forced to the fuel injection pump.In this case,fuel tank is placed away from engine or at lower level than the engine.This system is most useful for automobiles using diesel as fuel.The fuel placed away from the hot engine,avoids the chances of fire hazards.
The single acting fuel feed pump contains following parts
07)Inlet & Outlet
A plunger arrangement is fitted in pressure chamber.The plunger is activated downward by a cam through roller tappet and plunger rod.On the opposite side of plunger,a plunger spring is employed by which the return stroke of plunger is performed.The fuel is led to the plunger space through suction valve and after getting compressed,the fuel moves out through pressure valve into the pressure chamber from where it goes to the filter and then to the fuel injection pump.To avoid the wastage of fuel,a leakage channel is provided,which collects heated fuel from the stuffing box and feeds it again to the inlet pipe.
During the upward stroke of plunger suction is created in plunger space and fuel is sucked in,through suction valve.During the downward stroke,caused by cam arrangement,the fuel below the plunger is compressed ,which forces suction valve to close and pressure valve (Outlet valve) to open.The fuel thus flows out under pressure1 kilogram per centimeter square into the pressure chamber.
The construction and working of fuel feed pump is so easy that anyone can understand it easily.
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