Intake device for multi-cylinder internal combustion engine.

摘要

In an intake device for a multi-cylinder internal combustion engine, comprising a pair of resonance chambers (Cr-l,Cr-r) and a pair of resonance passages (18), the resonance chambers and the resonance passages are disposed in parallel in a V-space in the internal combustion engine with a dividing wall (24) interposed therebetween, thereby providing a compactified intake system. In the intake device, the resonance chambers are defined in one of upper and lower assembly box portions (21), while the resonance passages are defined in the other assembly box portion, and an on-off valve (25) capable of changing suction characteristics of the internal combustion engine being provided in a plate-like valve unit dividing opened surfaces of the two box portions. This enables a reasonable layout of the on-off valve. Further, in the intake device, the resonance chambers are capable of communicating with each other through a communication chamber having a predetermined volume. This ensures both of a resonance supercharge effect and an inertia supercharge effect.