Controller and control method for internal combustion engine

A controller for an internal combustion engine, wherein the internal combustion engine includes

• a first bank,
• a second bank,
• a first forced-induction device, which is located in both of a first intake passage and a first exhaust passage for the first bank and has a first turbine located in the first exhaust passage,
• a first bypass passage, which bypasses the first turbine and connects a section of the first exhaust passage that is upstream of the first turbine in an exhaust flow to a section of the first exhaust passage that is downstream of the first turbine in the exhaust flow,
• a first wastegate, which opens and closes a flow path of the first bypass passage,
• a first electric actuator, which moves the first wastegate so as to open and close the first wastegate,
• a second forced-induction device, which is located in both of a second intake passage and a second exhaust passage for the second bank and has a second turbine located in the second exhaust passage,
• a second bypass passage, which bypasses the second turbine and connects a section of the second exhaust passage that is upstream of the second turbine in an exhaust flow to a section of the second exhaust passage that is downstream of the second turbine in the exhaust flow,
• a second wastegate, which opens and closes a flow path of the second bypass passage, and
• a second electric actuator, which moves the second wastegate so as to open and close the second wastegate,
• the controller comprising:
• a calculation section configured to calculate a first requested drive current for moving the first wastegate to a target opening degree, and calculate a second requested drive current for moving the second wastegate to a target opening degree;
• an output section configured to supply the first electric actuator with a drive current that matches with the first requested drive current and supply the second electric actuator with a drive current that matches with the second requested drive current;
• a learning section configured to
• perform a first learning process that changes a first drive current, which is supplied to the first electric actuator, in a stepwise manner from a state where the first wastegate is stationary in a given first standstill position and learns, as a first learning value, an amount of change in the first drive current that is made until the first wastegate is determined to be moved, and
• perform a second learning process that changes a second drive current, which is supplied to the second electric actuator, in a stepwise manner from a state where the second wastegate is stationary in a given second standstill position and learns, as a second learning value, an amount of change in the second drive current that is made until the second wastegate is determined to be moved;
• and
• a correction section configured to correct the first requested drive current based on the first learning value and correct the second requested drive current based on the second learning value.

A method for controlling an internal combustion engine, wherein the engine includes a forced-induction device, which is located in both of an intake passage and an exhaust passage and has a turbine located in the exhaust passage, a bypass passage, which bypasses the turbine and connects a section of the exhaust passage that is upstream of the turbine in an exhaust flow to a section of the exhaust passage that is downstream of the turbine in the exhaust flow, a wastegate, which opens and closes a flow path of the bypass passage, and an electric actuator, which moves the wastegate so as to open and close the wastegate, the method comprising:

• calculating a requested drive current for moving the wastegate to a target opening degree;
• supplying the electric actuator with a drive current that matches with the requested drive current;
• changing the drive current in a stepwise manner from a state where the wastegate is stationary in a given standstill position;
• determining whether the wastegate is moved by changing the drive current in a stepwise manner;
• performing a learning process that learns, as a learning value, an amount of change in the drive current that is made until the wastegate is determined to be moved;
• and
• performing a correction process that corrects the requested drive current based on the learning value.

A non-transitory computer-readable storage medium storing a program that causes a processor to perform a control process for controlling an internal combustion engine that includes a forced-induction device, which is located in both of an intake passage and an exhaust passage and has a turbine located in the exhaust passage, a bypass passage, which bypasses the turbine and connects a section of the exhaust passage that is upstream of the turbine in an exhaust flow to a section of the exhaust passage that is downstream of the turbine in the exhaust flow, a wastegate, which opens and closes a flow path of the bypass passage, and an electric actuator, which moves the wastegate so as to open and close the wastegate, wherein the control process comprises:

• calculating a requested drive current for moving the wastegate to a target opening degree;
• supplying the electric actuator with a drive current that matches with the requested drive current;
• changing the drive current in a stepwise manner from a state where the wastegate is stationary in a given standstill position;
• determining whether the wastegate is moved by changing the drive current in a stepwise manner;
• performing a learning process that learns, as a learning value, an amount of change in the drive current that is made until the wastegate is determined to be moved;
• and
• performing a correction process that corrects the requested drive current based on the learning value.