Control device and control method for internal combustion engine

摘要

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.

主权项

1. A control device of an internal combustion engine having a supercharger arranged at an upstream side of a throttle valve, an EGR passage recirculating, as EGR, a part of exhaust gas from an upstream side with respect to the supercharger and an EGR control valve disposed at some midpoint in the EGR passage, the control device comprising:
an EGR ratio prediction unit that predicts, in advance, a change of an EGR ratio in a cylinder of the internal combustion engine which is caused by a change of an opening degree of the EGR control valve; and an intake control device that controls a quantity of intake air, and the EGR ratio prediction unit determining, according to at least an engine operating condition, a predetermined position in an intake system at which the EGR ratio changes at a timing that is a time point in advance of a timing at which the EGR ratio in the cylinder changes due to the change of the opening degree of the EGR control valve by an intake control device response time required for a quantity of fresh air in the cylinder to start to change after changing the quantity of the intake air by the intake control device, and predicting the EGR ratio at the predetermined position, and the intake control device being controlled on the basis of the EGR ratio at the predetermined position.