Control system for internal combustion engine

A control method for an internal combustion engine having a plurality of cylinders, a cylinder halting mechanism for halting operation of at least one of said plurality of cylinders by stopping operation of at least one intake valve of said at least one cylinder, and an intake air control valve for controlling an amount of air supplied to said engine, said intake air control valve being a throttle valve disposed upstream of said at least one intake valve, said control method comprising the steps of:

• increasing a number of operating cylinders in an idling condition of said engine, and continuing the idling operation of said engine after the increase in the number of operating cylinders;
• changing an opening of said intake air control valve when increasing the number of operating cylinders, by switching a basic opening of said intake air control valve from a first basic opening corresponding to the number of operating cylinders before the increase in the number of operating cylinders to a second basic opening corresponding to the number of operating cylinders after the increase in the number of the operating cylinders, the second basic opening being greater than the first basic opening;
• and
• correcting the basic opening in the closing direction during a predetermined time period when increasing the number of operating cylinders,
• wherein a correction amount for correcting the basic opening in the decreasing direction is set to a predetermined amount at the same time the basic opening is switched in said changing step, and thereafter the correction amount is gradually decreased.

A control system for an internal combustion engine having a plurality of cylinders and a cylinder halting mechanism for halting operation of at least one of said plurality of cylinders by stopping operation of at least one intake valve of said at least one cylinder, said control system comprising:

• an operation control unit configured to increase a number of operating cylinders in an idling condition of said engine, and to continue the idling operation of said engine after the increase in the number of operating cylinders;
• an intake air control valve configured to control an amount of air supplied to said engine, said intake air control valve being a throttle valve disposed upstream of said at least one intake valve;
• and
• an intake air amount control unit configured to change an opening of said intake air control valve when said operation control unit increases the number of operating cylinders,
• wherein said intake air amount control unit comprises
• a switching unit configured to switch a basic opening of said intake air control valve from a first basic opening corresponding to the number of operating cylinders before the increase in the number of operating cylinders to a second basic opening corresponding to the number of operating cylinders after the increase in the number of the operating cylinders, the second basic opening being greater than the first basic opening;
• and
• a correcting unit configured to correct the basic opening in the closing direction during a predetermined time period when increasing the number of operating cylinders,
• wherein said correcting unit is configured to set a correction amount for correcting the basic opening in the decreasing direction to a predetermined amount at the same time said switching unit switches the basic opening, and thereafter gradually decrease the correction amount.