Fuel supply amount control system for internal combustion engines

Claim 1

A fuel supply amount control system for an internal combustion engine having an exhaust passage, an intake passage, an exhaust gas recirculation passage extending between said exhaust passage and said intake passage, and exhaust gas recirculation valve means arranged across said exhaust gas recirculation passage, for recirculating part of exhaust gases emitted from said engine to said intake passage, comprising: valve lift-detecting means for detecting an actual valve lift amount of said exhaust gas recirculation valve means; operating condition-detecting means for detecting operating conditions of said engine; desired valve lift-determining means for determining a desired valve lift amount of said exhaust gas recirculation valve means, based on operating conditions of said engine detected by said operating condition-detecting means; exhaust gas recirculation valve control means for controlling said exhaust gas recirculation valve means, based on said desired valve lift amount determined by said desired valve lift-determining means and said actual valve lift amount detected by said valve lift-detecting means, when said engine is in a predetermined operating region where conditions for executing exhaust gas recirculation control are satisfied; basic fuel injection-calculating means for calculating a basic fuel supply amount, based on operating conditions of said engine detected by said operating condition-detecting means; correction coefficient-setting means for setting a correction coefficient for correcting said basic fuel supply amount, based on said actual valve lift amount and said desired valve lift amount, when said engine is in said predetermined operating region; and basic fuel amount-correcting means for correcting said basic fuel amount, based on said correction coefficient.