Intake and exhaust control system for automobile engine

Claim 1

An engine control system for controlling an internal combustion engine equipped with a mechanical supercharger, said engine control system comprising: an engine including a plurality of cylinders, first intake ports, second intake ports, provided separately from said first intake ports, and exhaust ports for said cylinders; intake means for introducing air into said cylinders, said intake means including a first intake passage in communication with each of said first intake ports, a second intake passage, provided separately from said first intake passage, in communication with each of said second intake ports, and a common intake passage connected to each first intake passage and each second intake passage; fuel injection means disposed in each first intake passage for injecting fuel into each of said cylinders; a first intake valve for opening and closing each of said first intake ports; a second intake valve for opening and closing each of said second intake ports; an exhaust valve for opening and closing each of said exhaust ports; valve drive means for driving said first intake valve, said second intake valve and said exhaust valve so as to open and close said first intake ports, said second intake ports and said exhaust ports, respectively, at a variable timing; and control means for detecting engine operating conditions and causing said valve drive means to retard opening and closing of each first intake port by said first intake valve with respect to opening and closing of each second intake port by said second intake valve when a specific range of engine operating conditions is detected.