How does an injection system work?
For the engine to run smoothly and efficiently, it must be
equipped with the right amount of fuel / air mixture according to its diverse
requirements.
Fuel injection system
Gasoline cars use indirect fuel injection. The fuel pump
sends the gasoline to the engine position and injects it into the intake
manifold. There is either a single injector for each cylinder or one or two
injection nozzles in the suction line.
Traditionally, the fuel and air mixture is
controlled by a carburetor, a tool that is by no means perfect.
controlled by a carburetor, a tool that is by no means perfect.
Its main disadvantage is that the only carburetor that
delivers the four-cylinder engine cannot give each cylinder exactly the same
fuel / air mixture as some cylinders are far from the carburetor than others.
One solution is to couple two carburetors, but it is
difficult to tune it properly. Instead, many cars are now fitted with fuel
injection engines, where the fuel is delivered in precise flashes. Engines that
are so equipped are usually more efficient and powerful than those that are carburetor
and can also be more economical and have less poisonous emissions.
Diesel fuel injection
The fuel injection system in gasoline cars is always
indirect, gasoline is injected into the intake manifold or intake duct, and not
directly into the combustion chambers. This ensures that the fuel mixes well
with the air before it enters the chamber.
However, many diesel engines use direct injection, in which
the diesel is injected directly into a cylinder filled with compressed air.
Others use indirect injection, in which diesel fuel is injected into a special
pre-combustion chamber, which has a narrow passage connecting it to the
cylinder head.
Only air is drawn into the cylinder. It is heated to such a
degree of compression that the atomized fuel injected at the end of the
compression stroke self-ignites.
Primary injection
All modern gasoline injection systems use indirect fuel
injection. A special pump delivers pressurized fuel from the fuel tank to the
engine compartment, where, under pressure, it is distributed individually over
each cylinder.
Depending on the particular system, the fuel is injected
either into the intake manifold or into the inlet through the injector. It
works just like a spray nozzle hose, ensuring that the fuel comes out in the
form of a shallow mist. The fuel is mixed with air passing through the intake
manifold or port, and the fuel-air mixture enters the combustion chamber.
Some cars have multipoint fuel injection, where each
cylinder is powered by its own injector. It is difficult and can be expensive.
Single-point injection is most commonly used when one cylinder feeds all
cylinders, or one injector for every two cylinders.
Nozzles
The injectors through which fuel is sprayed are screwed in
first into the injectors either in the intake manifold or in the cylinder head
and angled so that the fuel is sprayed in the direction of the intake valve.

Another popular system is synchronized injection (pulse
injection), when fuel is supplied in batches that coincide with the cylinder
intake stroke. As in the case of continuous injection, the programmed injection
can also be controlled either mechanically or electronically.
The earliest systems were mechanically controlled. They are
often referred to as petrol injection, and the fuel flow is controlled by a
mechanical regulator assembly. These systems suffer from the drawbacks of
mechanical complexity and a bad reaction to gas shutoff.
There are two types:
Mechanical Injection system
Electronic Injection system
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