Air supply control systems for internal combustion engines

Abstract

An air supply control system for an internal combustion engine comprises first and second turbosuperchargers, an exhaust cutoff valve operative to open and close one of separated exhaust passages in which a turbine of the second turbosupercharger is disposed, a first valve driving device for controlling the exhaust cutoff valve so that only the first turbosupercharger works when intake air mass flow fed to the engine is to be relatively small and both of the first and second turbosuperchargers work when the intake air mass flow is to be relatively large, an exhaust bypass valve operative to open and close an exhaust bypass passage provided for forming a partial exhaust passage detouring the exhaust cutoff valve, a second valve driving device for causing the exhaust bypass valve to open the exhaust bypass passage when intake air pressure applied to the engine reaches a predetermined value under a condition in which the intake air mass flow is to be relatively small, a waste gate valve operative to open and close a bypass passage provided for forming a partial exhaust passage detouring the turbines of the first and second turbosuperchargers, and a third valve driving device for causing the waste gate valve to open the bypass passage when the pressure of intake air reaches substantially the predetermined value under a condition in which the intake air mass flow is to be relatively large.