Multi Point Fuel Injection (MPFI) System | Types, Advantages, Disadvantages

By | January 8, 2019

What is multi point fuel injection (MPFI) system?

Multi point fuel injection (MPFI) is a technique of fuel injection in petrol (or gasoline) engines.

Note: Petrol (or gasoline) engines are sometimes also known as spark ignition (SI) engine.

In general, a petrol engine uses carburetor to mix air and fuel but it has poor response acceleration and deacceleration. Another big problem with carburetor is increased emissions.

In MPFI fuel is injected directly in the cylinder with the help of multiple fuel injectors. These fuel injectors help in injecting precise quantity of fuel into the combustion chamber.

These fuel injectors also produce better atomization and swirl of fuel in the combustion chamber.

multi point fuel injection (MPFI) system

Types of multi point fuel injection (MPFI) systems

There are basically three types of MPFI systems.

  1. Sequential multi point fuel injection system

  2. Simultaneous multi point fuel injection system

  3. Batched multi point fuel injection system

In the sequential MPFI system, injection is timed to overlap with intake stroke of each cylinder.

In the simultaneous MPFI system, fuel is inserted to all cylinders at the same time.

In the batched MPFI system, fuel is injected to the cylinders without bringing their intake stroke together.

Advantages of multi point fuel injection (MPFI) system

  • It increases fuel efficiency of the engine
  • With MPFI system vehicle have less emissions
  • Better atomization of fuel
  • It encourages better utilization and distribution of fuel with in an engine
  • Smooth operation of engine
  • It reduces the difference in power, produced by each cylinder
  • Better acceleration and deacceleration of engine
  • In improves durability and functionality of engine
  • It is reliable
  • It improves cold start characteristics of the engine
  • It reduces vibrations in the engine

Disadvantages of multi point fuel injection (MPFI) system

  • There could be a case of misfiring sometimes
  • Regular inspection of fuel injectors is required
  • It is costly as compared to conventional systems

Below are some frequently asked questions related to Multi point fuel injection (MPFI) systems.

Where is MPFI used?

Multi point fuel injection (MPFI) systems are used in Gasoline (or petrol) engines to inject fuel.

What is the function of MPFI?

The function of Multi point fuel injection (MPFI) system is to inject fuel inside the cylinder from different points so that it atomizes in a better way.

What does MPFI mean?

MPFI is the short form of Multi point fuel injection.

Also read:

What are applications of diesel engines?

What are disadvantages of two stroke engines?

What are applications of Internal combustion engines?

What are different types of engine cooling systems?

Featured image attribution: Image attribution:┬áBy Flickr user storem –, CC BY-SA 2.0,


Types of MPFI systems:

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