PURPOSE: To perform purification of exhaust gas through utilization of an internal EGR and to prevent the occurrence of a misfire owing to the internal EGR by a method wherein the control target value of a valve timing is limited so that an amount of exhaust gas re-sucked in a combustion chamber owing to overlap of a valve is prevented from exceeding a given value.
CONSTITUTION: An intake valve M5 and an exhaust valve M6 are respectively driven at a given timing in synchronism with operation of an internal combustion engine M1 and an intake passage M3 and an exhaust passage M4, both communicated with a combustion chamber M2, are respectively opened and closed. Namely, based on the operation state of an internal combustion engine M1 detected by a means M8, a control target value is calculated by a means M9 and a means M7 to vary a valve timing so that valve overlap is continuously varied according to the control target value is controlled by a means 10. In this case, a control target value is limited by a means M11 so that an amount of exhaust gas re-sucked to the combustion chamber M2 by the valve overlap is prevented from exceeding a given value responding to an operation state.
OSANAWA TADAHISA
KATOU KAZUSHI
GOTO JUNJI
ENDO KOJI
SONE SHIGERU
