Published On: Fri, Apr 12th, 2013

✔ How does a fuel injection pump works – video tutorial.

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This is a very valuable topic in mechanical engineering; this topic is very rarely discussed in the internet. We are giving you the opportunity to learn and understand more about the basics of how a fuel injection pump works; this pump is normally referred to as FIP, the short form of fuel injection pump.

This fuel injection pump or an FIP is the heart of an automobile and engine is its stomach. The FIP does the function as of human heart, it pumps the fuel. The function of stomach is to process it to energy, that’s what is done by the engine. FIP is pumping the fuel to the engine and engine is processing it and delivers as mechanical energy (torque).

Which are the various types of fuel injection pumps?

  1. In-line fuel pump
  2. Rotary fuel pump
  3. Electric fuel pump

The function of a FIP is to pump or create a flow of fuel to the engine

In this topic we will discuss about the components and working of a rotary fuel injection pump.

Components of FIP

Components of FIP

Main components of a rotary FIP:

  1. Drive shaft
  2. Governor weight retainer
  3. Head
  4. Metering valve
  5. Rotor
  6. Throttle shaft
  7. Governor arm

Drive shaft: this part is connected to the engine, from which it is receiving its drive.

Governor weight retainer: this unit is linked to the drive shaft and looks like a flower, with 4-6 petals. These petals will be having weights inside.

Head: as shown in the figure, this is the part to which the injectors, metering valve; rotor connected, hence the most integral part of an FIP.

Metering valve: this is a part of the head and is connected through internal galleries to the rotor pump.

Rotor: this is a type of vane pump, which is use to pump the fuel.

Throttle shaft: the accelerator cable is been connected to the throttle shaft.

Governor arm: the governor is linked to the throttle lever through the governor arm.

Working of a fuel injection pump (rotor type) explained:

Video explaining the working of fuel injection pump (fip)

As the drive shaft rotates, the governor weight retainer also rotates. The governor weight retainer works with the principle of centrifugal force. As the governor weight retained rotates it pushes the weights inside the petals of the governor and intern pushes the governor arm. As the governor arm moves towards the head, the metering valve also moves and closes the gallery inside the head (connecting the rotor pump and metering valve) cutting or limiting the fuel supply through internal galleries of the metering valve to which the injectors are connected.

Video explaining the working of Rotary (vane pump) of FIP

Let’s see how the fuel demand occurs: as show in the figure and also explained in the videos, the accelerator cable is connected to the throttle shaft. So as the driver operated the accelerator pedal the fuel demand occurs. The throttle lever pushes the governor arm backwards and hence the metering valve moves, as it is linked to the governor arm. This will result in the opening of the internal port of metering valve to rotor and fuel is supplied.

So the cross functions of the governor arm and throttle lever creates the fuel demand. They are controlled by the engine RPM and demand given by the driver through the accelerator pedal.

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  1. Rachit agarwal says:

    Fuel demand explanation is OK. But how it does it pumps the fuel in exact firing order and timing in engine?

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