Patent ID: 8528525

Claim:
A fuel injection controlling system of an internal combustion engine, comprising: an accelerator manipulator; an accelerator manipulated variable detection sensor configured to detect a manipulated variable of the accelerator manipulator; a rotation speed sensor configured to detect a rotation speed of the internal combustion engine; a throttle valve; a throttle valve drive motor configured to open and close the throttle valve in response to the manipulated variable of the accelerator manipulator; a throttle opening degree sensor configured to detect an opening degree of the throttle valve; and a controller configured to control the throttle valve drive motor and to compute basic injection time (Ti) of fuel, the controller comprising: a memory configured to memorize, as a carbon adhesion judgment value (IXREF), a throttle opening degree (θTH) at a moment when a rotation speed (Ne) detected with the rotation speed sensor reaches a target idle rotation speed (NeIdle) by increasing the throttle opening degree (θTH); a corrector configured to correct the basic injection time (Ti) with the carbon adhesion judgment value (IXREF) so as to correct an air-fuel ratio toward a leaner side as the carbon adhesion judgment value (IXREF) increases; an Ne—Th map configured to obtain the basic injection time (Ti) of the fuel based on the rotation speed (Ne) and the throttle opening degree (θTH) of the internal combustion engine; an Ne—Pb map configured to obtain the basic injection time (Ti) of the fuel based on an intake pipe internal negative pressure (Pb) and the throttle opening degree (θTH); and a map selector configured to select the Ne—Pb map when the throttle opening degree (θTH) is less than a prescribed map selection standard opening degree (θMAP) and to select the Ne—Th map when the throttle opening degree (θTH) is not less than the map selection standard opening degree (θMAP), wherein the controller is configured so that correction of the basic injection time by the corrector is performed with respect to the basic injection time (Ti) of the fuel computed by using the Ne—Th map, and wherein the controller is configured so that correction of the basic injection time by the corrector is not performed with respect to the basic injection time (Ti) of the fuel computed by using the Ne—Pb map.