Internal EGR control system for internal combustion engine

摘要

There is provided an internal EGR control system for an internal combustion engine, which is capable of ensuring an excellent combustion state by properly controlling an internal EGR amount. The internal EGR control system is comprised of a variable valve operating mechanism 60 for controlling an internal EGR amount of combustion gases caused to remain in cylinders 3a by changing valve-closing timing CAEXVC of exhaust valves 9, target internal EGR amount-setting means 2 for setting a target internal EGR amount of the internal EGR amount EGRINC according to detected operating conditions NE, PMCMD of the engine 3, valve-closing timing-calculating means 2 for calculating valve-closing timing of the exhaust valves 9 based on the set target internal EGR amount EGRINC, valve-closing timing-correcting means 2 for correcting the calculated valve-closing timing of the exhaust valves according to the acquired wall surface temperature parameter TW indicative of wall surface temperature of the cylinder 3a, and control means 2 for controlling the variable valve operating mechanism based on the corrected valve-closing timing of the exhaust valves 9.