Figure 7. Typical Intake Manifold.

Principles of Gasoline And Disesel Fuel Systems
Page Navigation
17

Intake Manifold

a. Description (figure 7). A properly designed intake manifold should

perform the following functions:

FIGURE 7. TYPICAL INTAKE MANIFOLD.

(1) Deliver the mixture to the cylinders in equal quantities and

proportions. This is important for smooth engine performance. The length

of the passages should be as near equal as possible to distribute the

mixture equally.

(2) Help to keep the vaporized mixture from condensing before it

reaches the combustion chamber. Because the ideal mixture should be

vaporized completely as it enters the combustion chamber, this is very

important. To reduce condensation of the mixture, the manifold passages

should be designed with smooth walls and a minimum of bends, which collect

fuel. Smooth flowing intake manifold passages also increase volumetric

efficiency.

(3) Aid in the vaporization of the mixture. To do this, the intake

manifold should provide a controlled system of heating. This system of

heating must heat the mixture enough to aid in