Multi Point Fuel Injection or MPFI System- Working, advantages

In this article, we will see Multi Point Fuel Injection System (MPFI) working, use, advantages, disadvantages | pdf, ppt, seminar report on MPFI system.


Despite the rapid development in carburetors which are cheap and efficient, the automobile industry prefers to use a gasoline injection system in spark ignition (S I Engines). Then, there must be some advantages of the gasoline injection system over the carburetor system which we are going to see it at the end of this article.

There are different types of gasoline injection systems in S I Engines, and one of them is a Multi-Point Fuel Injection System or MPFI System. In this article, we are going to learn about components, use, and working of multi point fuel injection system.

Read about Working of Simple Carburetor

If you compare MPFI system/MPFI engine with single-point fuel injection, single-point fuel injection has only one centrally located fuel injector which supplies fuel to all cylinders, but in a multi point fuel injection system, each cylinder has a separate fuel injector that supplies fuel from the fuel tank to the cylinders.

MPFI System Diagram

MPFI System- Working, advantages

Diagram of Multi Point Fuel Injection System (MPFI)

Why Multi Point Fuel Injection System (MPFI):

Multi-Point Fuel Injection System aka the MPFI system was originally only developed for the airplane engines. Nowadays, it is widely used in light commercial vehicles. MPFI system is the most advanced gasoline injection system the automobile industry currently has.

MPFI system is not a standalone mechanical system. It is a perfect blend or combination of electronics, mechanical, computer and electrical engineering that make this system more advanced.

Students from universities widely choose this topic for giving a seminar at their colleges. This article will definitely help them to prepare a seminar report on the Multi-Point Fuel Injection System (MPFI).

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Components in Multi Point Fuel Injection System (MPFI):

There are different components used in the MPFI system as follows:

  1. A mechanical solenoid injector
  2. The electronic control unit (ECU)  – It controls ignition timing and quality of the fuel.
  3. Electronic sensors to monitors different output such as exhaust gas temperature, coolant temperature, speed, and throttle position.
  4. Air filters to remove solid particles from the atmospheric air.

Working of  MPFI System:

  1. In the MPFI system, using the fuel pump which is driven by the electric motor is used to spray fuel into the engine intake manifold.
  2. This technique helps to provide an accurate air-fuel ratio at all operating conditions.
  3. The suction pressure of the engine is used to spray the fuel into the cylinders ( In carburetors, the vacuum is used to provide the fuel).
  4. As shown in the figure, you can see that a single injector is placed on the intake port of the different cylinders.
  5. Using the electrical fuel pump, fuel from the fuel tank supplies to each fuel injector equally.
  6. The process of fuel injection occurs simultaneously in each injector once in every rotation.

Classification of  MPFI system:

MPFI system is classified into systems as follows:

1. D-MPFI System:
D-MPFI is a manifold fuel injection system.

2. L-MPFI System:
L-MPFI is a port fuel injection system.

Advantages of MPFI system:

  • The power generated by the engine is more than the carburetion system.
  • Due to the accurate mixture of air-fuel supplied to each cylinder, the difference between power generated at each cylinder is negligible.
  • Engine vibrations from MPFI equipped engines are very less, hence the life of MPFI system equipped engines is high.
  • This system is very responsive in case of sudden acceleration or deceleration.
  • Lower fuel consumption leads to better mileage.
  • The volumetric efficiency of MPFI is high.

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Disadvantages of MPFI system:

  • The system is complex hence costly.
  • It requires more space.

Multi-Point Fuel Injection System (MPFI) system uses in most of the modern light vehicles available in the market. The first MPFI engine equipped vehicle is Daewoo Matiz.

MPFI System- Working, advantages -Daewoo Matiz

Diagram of Daewoo Matiz MPFI

Out Downloads:

Download the MPFI System ppt from here.

Download MPFI System pdf from here.

If you have any queries or suggestions regarding this article about the MPFI system, feel free to put it in the comment box below.

4 thoughts on “Multi Point Fuel Injection or MPFI System- Working, advantages”

      • Under the heading above “Working of MPFI System:” your point number 6 states: “The process of fuel injection occurs simultaneously in each injector once in every rotation.” In a 4 stroke engine this process would not occur in every rotation but in every other rotation.

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