Intake system in multi-cylinder type internal combustion engine.

摘要

An intake system in a multi-cylinder type internal combustion engine (E) comprises throttle valves (21) disposed in a plurality of intake passages (W) commonly connected to an air cleaner (13), and fuel injection valves (11) disposed in the intake passages (W) downstream of the throttle valves (21) in an intake direction. In such intake system, a plurality of funnel-shaped portions (19,1,2,3) are provided in a throttle body (12) having opposite ends directly coupled to an intake manifold (7) and an air cleaner (13), respectively, and each of the throttle valves (21) is disposed in the throttle body (12), so that its upstream end in the intake direction (16) is located at least on the corresponding funnel-shaped portion (19,1,2,3), when the throttle valve (21) is fully opened. The throttle body (12) includes ports provided therein, which are opened into the intake passages (W) between a coupled surface of the throttle body (12) to the intake manifold (7) and the throttle valves (21), respectively, and which communicate with one another. This provides an increase in space efficiency and an increase in intake inertial effect.