Abstract: In a case where a driving state is switched from a high load to a low load in a non-turbo charge region and an external EGR is stopped, at a timing T01 at which an EGR control valve (21) is closed, a valve overlap quantity between an intake valve and an exhaust valve is, as a low load transient time provisional value, controlled in a direction such that the valve overlap between the intake and exhaust valves is once contracted. Then, a target value of the valve overlap quantity between the intake and exhaust valves at a timing T21 preceded by a response time ?t of the variably operated valve mechanism (28) from a timing T31 at which the opening angle of the EGR control valve (21) is modified from the low load transient time provisional value to the target value at the time of the low load.

Abstract: In a case where EGR is started in a supercharging region, an opening degree of a waste gate valve (17) is changed at a timing T1 at which an EGR ratio in a first predetermined position changes by valve open of an EGR control valve (21). In a case where EGR is started in a non-supercharging region, a throttle valve (5) is changed at a timing T2 at which an EGR ratio in a second predetermined position changes by valve open of the EGR control valve (21). With these controls, it is possible to suppress an occurrence of torque step upon start of the EGR without distinction between the supercharging region and the non-supercharging region.

Abstract: In a case where a driving state is switched from a high load to a low load in a non-turbo charge region and an external EGR is stopped, at a timing T01 at which an EGR control valve (21) is closed, a valve overlap quantity between an intake valve and an exhaust valve is, as a low load transient time provisional value, controlled in a direction such that the valve overlap between the intake and exhaust valves is once contracted. Then, a target value of the valve overlap quantity between the intake and exhaust valves at a timing T21 preceded by a response time ?t of the variably operated valve mechanism (28) from a timing T31 at which the opening angle of the EGR control valve (21) is modified from the low load transient time provisional value to the target value at the time of the low load.

Abstract: In a case where EGR is started in a supercharging region, an opening degree of a waste gate valve (17) is changed at a timing T1 at which an EGR ratio in a first predetermined position changes by valve open of an EGR control valve (21). In a case where EGR is started in a non-supercharging region, a throttle valve (5) is changed at a timing T2 at which an EGR ratio in a second predetermined position changes by valve open of the EGR control valve (21). With these controls, it is possible to suppress an occurrence of torque step upon start of the EGR without distinction between the supercharging region and the non-supercharging region.