Intake system of plural cylinder internal combustion engine.

摘要

An intake system of a multi-cylinder internal combustion engine including a common inlet duct (10), first and second resonance ducts (12a, 12b) branched from the downstream end of the inlet duct (10), first and second resonance chambers (14a, 14b) leading to the first and second resonance ducts (12a, 12b), respectively, a plurality of first intake ducts (9a) for connecting the first resonance chamber (14a) to a first group of cylinders (1a), respectively, having ignition timings set not to come adjacent to each other, respectively, a plurality of second intake ducts (9b) for connecting the second resonance chamber (14b) to a second group of cylinders (1b), respectively, having ignition timings set not to come adjacent to each other, a common intake chamber (15) capable of communicating with both the resonance chambers (14a, 14b) via a communication port (16) which can be closed by a valve (17a, 17b), and an actuator (24) for opening and closing the valve (17a, 17b) at least in response to the engine revolution. A valve operating system is provided to control at least closure timing of intake valves (20a, 20b) at least in response to the engine revolution.