CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE

A control system (1) for an internal combustion engine includes a control unit (50). The control unit (50) causes the injectors (43A to 43D) configured to inject fuel into cylinders (45A to 45D) to perform pilot injections, followed by a main injection, and to perform after-injections at a timing of a temperature increase request. The temperature increase request is when the temperature of exhaust gas is to be increased. A target ignition delay acquiring unit of the control unit (50) acquires a target ignition delay that is a target ignition delay of a main fuel to be injected into the cylinders (45A to 45D) during the main injection. A target pilot injection volume setting unit of the control unit (50) sets a target pilot injection volume of the pilot injection that can ensure the after-injection volume of the after-injection is sufficient. A main injection timing setting unit of the control unit (50) sets a main injection timing where the main fuel injected into the cylinders (45A to 45D) is combusted, along with the pilot injection having the target pilot injection volume, with the target ignition delay.