A system and method are disclosed for controlling idle speed of an internal
combustion engine. The system includes an engine speed sensor producing an
engine speed signal indicative of a rotational engine speed of an internal
combustion engine, and a control circuit. The control circuit controls the
rotational speed of the engine between an idle speed reference and a
maximum speed reference. The control circuit also modifies the idle speed
reference as a function of the engine speed. Additionally, the control
circuit may determine an engine acceleration rate as a function of the
engine speed, and modify the idle speed reference as a function of the
engine speed and the engine acceleration rate.
