Controller for internal combustion engine

Abstract

A controller for an internal combustion engine is disclosed that improves drivability by always stabilizing combustion. A combustion state is detected based on an engine speed fluctuation every cylinder, and whether combustion is stable is determined. When combustion is stable, whether the condition of executing fuel stability deteriorating operation is satisfied is determined. When combustion is unstable or the condition of executing the fuel stability deteriorating operation is satisfied, a control item adapted to current operating state is selected from control items of ignition timing, ignition method, in-cylinder flow velocity, EGR rate, and air-fuel ratio, and a control is performed so that the combustion velocity and the combustion pressure are stabilized. In the ignition control method, a spark is made a plurality of times by a spark plug. In the control of the in-cylinder flow velocity, a gas flow velocity in a cylinder is increased by strengthening a swirl flow.

Dependencies are inferred from the claim text.