Popular Types Of Fuel Injection Systems Used In Automobiles

By Author: Nate Rodney
Total Articles: 499
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Fuel injection system (FIS) is the primary fuel delivery system in automotive engines that injects fuel to facilitate combustion. FIS replaced carburetors and all modern vehicles now have fuel injection system. Though both carburetors and fuel injection systems perform same task of supplying fuel, they differ in the way they do it.
Fuel injection system is more efficient as it contains sensors that measure optimum quantity of fuel and air based on the environment and driving style and then send to cylinders for combustion. On the other hand, carburetors send fuel and air randomly without measuring. There are different types of fuel injection systems. In this article, we will discuss about three popular types of fuel injection systems.

Throttle body fuel injection system
Throttle body injection system is the first type of fuel injection that replaced carburetors by incorporating electrically controlled injector valves into the throttle body. They are designed in such a way that automakers can replace carburetors without redesigning their engines. Also called as single-point injection system, it is the simplest ...
... FIS model with a single large injector mounted at the throttle plate and hence the name.

Unlike multi-point injection systems, single-point system uses only one injector to inject fuel to all the cylinders. Single-point body injection measures the right amount of fuel to be sent by using sensors.

Multi-point or port fuel injection system
Unlike throttle body injection, multi-point fuel injection system has multiple ports or fuel injectors to inject fuel. Each cylinder of the engine will have an independent injector dedicated to inject optimal amount of fuel and air mixture which results in more accurate fuel usage and quick engine responses.

There are three different types of multi-port fuel injection system. They are
Simultaneous: In this type of fuel injection, all injectors pump fuel into the cylinders at the same time or in a group.
Sequential: Sequential fuel injection triggers each injector individually i.e., fuel is injected into each cylinder at different times based on their working and fuel intake requirement.
Batched: In this type of multi-port fuel injection, fuel is injected into cylinders in batch-wise manner i.e., to few cylinders at one time and to the remaining at other time.

Direct fuel injection system
Direct fuel injection is an improved type of multi-port fuel injection. It also comes with sensors that measure the amount of fuel to be sent accurately to the cylinders but with high pressure. It then mixes with air inside the cylinders and results in complete combustion that means whole of fuel sent is burnt and results in the increase in the power, fuel efficiency and lower toxic emissions.

Direct fuel injection systems are high pressure systems. They are exposed to more heat and pressure. Hence, quality materials that can withstand the heat and high pressure are used and are hence expensive than all other types fuel injection systems.

These are the popular types of fuel injection systems. Among the above, throttle body injection is rarely seen in the modern vehicles as the later types are comparatively more efficient.

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