Patent ID: 6990953

Claim:
An idle rotation speed control device of an internal combustion engine, comprising: a mechanism which regulates an intake air flow rate of the internal combustion engine; a sensor which detects an engine rotation speed of the internal combustion engine; and a programmable controller programmed to: calculate, when the engine rotation speed is different from an target idle engine rotation speed, a feedback correction amount so that the intake air flow rate is gradually varied in a direction such that the engine rotation speed approaches the target idle engine rotation speed; calculate an increase correction amount of the intake air flow rate based on the engine rotation speed; control, when the engine rotation speed drops below the target idle rotation speed, the mechanism based on the sum of the feedback correction amount and increase correction amount; determine whether or not the engine rotation speed satisfies a preset increase correction termination condition; and set, when the engine rotation speed satisfies the increase correction termination condition, the sum of the feedback correction amount and increase correction amount when the termination condition is satisfied, to a new feedback correction amount, while setting the increase correction amount for subsequent control to be zero.