What are the three types of fuel injectors?

The combustion engine in our cars would not function without fuel. Supplying this essential fuel into the combustion chambers are the fuel injection systems. Many attributes of your car are highly influenced by the type of fuel injection system its engine has, mileage, ride quality, engine life, etc. A fuel injection system is a mechatronic circuit that is the combination of mechanical and electronic circuits to supply fuel of ideal volume into the engine.

Since the fuel injection system is such a vital component, engineers around the globe have evolved it to its most efficient and effective version. In this day and age, while there are various types of fuel injection systems available, the broad categorization brings them down to four main types: Single point fuel injection, Multi-point fuel injection, Sequential fuel injection, and Direct fuel injection. Let’s go through these categories one by one and understand their functionality.

A single-point injection system features a common fuel injector for all the cylinders in the combustion chamber of the engine. This is the oldest and simplest form of the fuel injection system. In place of the carburettor, the single-point injection uses one or two fuel injector nozzles in the throttle body which is why it’s called Throttle body injection (TBI) as well.

The fuel is sprayed in all cylinders at the same time, however, as opposed to the carburettor jet, it comes from an injector and can be monitored by an electronic control unit (ECU). While it has an edge over the carburettor, it has a slight disadvantage that since it uses a single injector it disturbs the performance of an engine at high RPMs and causes rough ride quality as the required fuel supply isn’t fulfilled. Moreover, a small fraction of fuel gets condensed outside the intake manifold of the cylinders and this causes fuel wastage.