Intake manifold for internal combustion engines

Abstract

In an internal combustion engine, an intake manifold has a main distributing chamber and an auxiliary distributing chamber disposed to overlap with the main distributing chamber at a location inward thereof. The main distributing chamber is divided by a partition wall into a primary distributing chamber and a secondary distributing chamber. The partition wall has a boss through which is formed an intake guide passage having one end opening in the auxiliary distributing chamber and directed toward a substantially central location of the chamber. The primary distributing chamber, the secondary distributing chamber and the intake guide passage leading to the auxiliary distributing chamber have respective mixture-inlet ports opening in a carburetor-mounting surface formed on the outer surface of the intake manifold and arranged thereon in a compact array. Thus, the intake guide passage has a simplified configuration, and also the intake manifold can have a compact size.