Function and Differences of Engine Inlet Manifold

The role of engine inlet manifold

The engine intake manifold refers to the section of pipe that distributes air from the intake pipe to each cylinder, and each cylinder has an engine intake manifold. The design of the engine intake manifold ensures that the intake distribution to each cylinder is reasonable and uniform. The intake manifold in car engine is located between the throttle valve and the engine intake valve. The reason why it is called a "manifold" is that after the air enters the throttle valve and is buffered by the manifold, the air passage is "divided" here, corresponding to the number of engine cylinders. For example, a four-cylinder engine has four passages, and a five-cylinder engine has five passages, which separately guide the air into each cylinder.

For a naturally aspirated engine, since engine inlet manifold is located after the throttle valve, when the engine throttle opening is small, the cylinder cannot suck enough air, which will cause a high vacuum in the manifold. When the engine throttle opening is large, the vacuum in the engine intake manifold will decrease. Therefore, injection fuel supply engines will install a pressure gauge on the engine intake manifold to supply the ECU to judge the engine load and provide appropriate fuel injection.

The function of the engine inlet manifold

On a multi-point electronic fuel injection engine, in order to eliminate intake fluctuation and ensure that each cylinder's intake is uniform, there are strict requirements for the shape and volume of the intake manifold and engine intake manifold. Each cylinder must have a separate engine intake manifold. Some engines have integrated the intake manifold with engine inlet manifold, while others are manufactured separately and connected with bolts. The inertia effect of the airflow: the airflow passing through the intake pipe at high speed has a certain inertia. The pressure wave effect of the airflow: by utilizing the intermittency and periodicity of the intake process to cause a certain airflow pressure wave in the intake pipe, the resonance of the pressure wave formed by reflection in the pipeline can be used to increase the intake flow rate.

The difference between engine intake pipe, intake channel, and engine intake manifold

The intake pipe refers to the section of pipe from the intake port to the point where it enters each cylinder, which is the main intake pipe of the engine and the total intake pipe. The intake channel is the channel from the air entering the engine body to the cylinder. It is mainly composed of channels designed on the cylinder head. The end of the intake channel is controlled by the intake valve.