Intake Manifold

The function of the intake manifold is to supply the intake charge to all the cylinders of the engine in equal proportion. It is connected between the carburetor/ throttling body and cylinder head. Depending on the number of cylinders the construction of the intake manifold is different.

The intake manifold is the major part of an engine that consists of cast iron or aluminum. As aluminum has the advantage of being lightweight it is generally preferred to cast the intake manifold. Currently, it is also made up of composite materials.

The intake manifold is consist of two parts i.e. plenum and runner

1) Plenum: The plenum connects all the runners together and it is comparatively larger in size. The one end of the plenum is connected to the carburetor or throttle body.

2) Runner: Runners connect the plenum to the individual cylinder head and it carries the air-fuel mixture or air from the plenum to the cylinder.

Depending on the number of plenums the intake manifold is divided as

1) Dual plane intake manifold: The plenum area in this type of intake manifold is split into two sections at the opening connected to the carburetor. Further, each plenum is connected to about 4 cylinder heads by using runners. In this type, the intake charge is divided by both plenums.

2) Single plane Intake manifold: The single plane intake manifold has only a single plenum section that is connected further to the cylinder heads by means of runners.

What is the function of the intake manifold?

1) The intake manifold is used to connect the carburetor or throttle body to the cylinder head and helps to supply the air or air-fuel mixture to all the cylinders in equal proportion.

2) In some intake manifolds, the fuel is spread inside of the intake manifold by using the fuel injectors.

3) The good intake manifold also avoids pressure loss.

4) The intake manifold also has the provision to mount different sensors for testing the density, oxygen amount of air, and other parameters.

5) The runner position sensor is mounted on the intake manifold which controls the opening of the flap inside of the intake manifold to control the flow of air.