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how a fuel injection system works

Almost every car on the Australian roads today is fitted with a powerful fuel injection system. A fuel injector puts fuel into a car’s internal combustion engine  – a process that basically makes the car run. With the evolution of technology, fuel injection systems come infused with complex computer systems that maximize every drop of fuel that is put into the car.

Earlier, we used to have carburettors that would give the combustion engine a mixture of fuel and air to run. It was only during the 1980s that carburettors started getting replaced by single point fuel injection systems instead.

So why would a device that mixes air and fuel for the combustion engine be replaced by a much more complex system that requires enormous fuel pressure? The answer lies in the strict emission laws that were passed during that period.

Carburettors would have a main circuit, idle circuit, accelerator pump, a power enrichment circuit and a choke – all of these came to use for specific functions and would require a separate amount of fuel individually.

The machine itself worked on the basis of engine suction that would drive the fuel for combustion. With the new laws in place, catalytic converters came into place that would convert pollutants into a purer form of air before leaving the exhaust system.

After that came the electrical carburettors that were even more complex than their mechanical counterparts. All in all, nothing seemed feasible or cost-effective until some refined work in technology introduced the early fuel injection systems.

Most cars today are fitted with updated versions of these systems that inject fuel into the engine after atomizing it through a small nozzle under high pressure.

Types of Fuel injecting systems

Single-Point or Throttle-Body Injection

In order to run, a car’s combustion engine needs a mixture of air and fuel. As the carburettors were becoming obsolete, they were replaced by a single-point or throttle body fuel injection system. It works on a very simple mechanism – injecting fuel in the car’s air intake manifold or the throttle. These systems typically have two or three injector nozzles that atomize the fuel before it goes into the engine through the throttle.

Being one of the earliest forms of injectors. A single-point injector is less precise than the succeeding, more complex and efficient multipoint systems. However, they are comparatively less expensive and are easier to maintain and service.

Port or Multipoint Fuel Injection

This is a system wherein a separate injector nozzle is inserted into each and every cylinder. It is also commonly known as Port injection, since the nozzle is placed near the intake port of these cylinders. The reason for this is to ensure that the fuel does not get wasted and is completely drawn into the cylinder. With this type of injection system there is no condensation of fuel in the intake manifold and it doesn’t need to be made of metal in order to conduct the heat of the engine. A multipoint injector ensures a better air-fuel ratio since it can meter more fuel in a precise manner. Also, a lightweight intake manifold gives engineers the opportunity to be more creative with the interior design.

Direct Injection

This is the most advanced version of a fuel injection system. Commonly found in diesel cars, this type of system is being introduced into Gasoline engines as well, commonly called DIG – direct engine gasoline. In this system, as the name suggests, the fuel is directly injected into the combustion chambers of a car past the valves. Being the most advanced of injection systems, it is also the most precise when it comes to fuel economy. A direct injection system helps produce low-emission engines which are best for the environment with their lean-burning capacities.

Pollution-control has been on the agenda for quite a number of years and the bad news is, we don’t seem to be progressing much with it. With the average number of cars on Australian roads increasing every year, the fumes and smoke have been increasing.

So do your bit, If your car is having a fuel consumption problem, for example, if it is stalling or cutting out unnecessarily – bring it in to your car mechanic to take a look.