Control device for internal combustion engine for selecting operation to calculate target throttle opening degree based on prediction of temporary reduction in charging efficiency of fresh air in acceleration

A control device for an internal combustion engine having a compressor disposed in an intake passage, a throttle disposed downstream from the compressor in the intake passage, and an EGR valve disposed in an EGR passage connecting an exhaust passage and an upstream side from the compressor in the intake passage, the control device configured to operate the throttle so as to increase a charging efficiency of an in-cylinder gas, and operate the EGR valve to increase an EGR rate of the in-cylinder gas, in an acceleration operation, the control device comprising:

• at least one processor;
• and
• at least one memory including at least one computer program, the at least one memory and the at least one computer program configured to cause the at least one processor, in the acceleration operation, to
• increase a target charging efficiency in accordance with a magnitude of acceleration requested of the internal combustion engine,
• calculate a target throttle opening degree based on the target charging efficiency, and select to calculate the target throttle opening degree by one of a first arithmetic operation, and a second arithmetic operation by which an increase speed of a throttle opening degree is restrained more than by the first arithmetic operation, and
• predict, by using a prediction model expressing dynamic characteristics of the internal combustion engine, whether temporary reduction occurs to a charging efficiency of fresh air in the in-cylinder gas by and during an increase of the EGR rate of the in-cylinder gas after an increase of the charging efficiency of the in-cylinder gas when the first arithmetic operation is applied to calculation of the target throttle opening degree based on the target charging efficiency which is increasing, in a case of shifting to the acceleration operation,
• wherein the at least one processor is caused to
• select to calculate the target throttle opening degree by the first arithmetic operation in response to a prediction that no temporary reduction occurs to the charging efficiency of the fresh air in the in-cylinder gas, and
• select to calculate the target throttle opening degree by the second arithmetic operation in response to a prediction that temporary reduction occurs to the charging efficiency of the fresh air in the in-cylinder gas, and
• wherein the at least one processor is caused to
• predict, by using the prediction model, an increase speed of the charging efficiency of the in-cylinder gas, and an increase speed of a charging efficiency of an EGR gas in the in-cylinder gas, that are obtained when the throttle is operated by using the target throttle opening degree calculated by the first arithmetic operation, and
• compare the predicted increase speed of the charging efficiency of the in-cylinder gas with the predicted increase speed of the charging efficiency of the EGR gas in the in-cylinder gas, and determine that temporary reduction occurs to the charging efficiency of the fresh air in the in-cylinder gas when the predicted increase speed of the charging efficiency of the EGR gas in the in-cylinder gas is higher than the predicted increase speed of the charging efficiency of the in-cylinder gas.