Abstract: A method for controlling a direct injection internal combustion engine by measuring both the degree of actuation of an accelerator pedal and the engine speed to provide optimal engine tuning parameters. According to the method, a table showing the pressure/air temperature ratio in the intake manifold is established, during engine tune-up, for each degree of actuation/speed pair. The pressure and temperature of the intake air are measured during normal operation, and the measured pressure/temperature ratio is formed. The opening angle of a throttle in the intake manifold is adjusted to make the ratio dependent on a set value read out of the table. Reverse reading of the table is performed to determine a virtual degree of accelerator pedal actuation on the basis of the measured speed and ratio, thereby providing at least one of the optimal engine tuning parameters.

Abstract: The speed of an internal combustion engine is monitored during the entry thereof into low-idle speed operation. The engine speed can thereby be slaved to a predetermined reference point value. When a predetermined engine condition occurs which is considered to require the engine to switch to idling speed, the set speed of the engine is forced downwardly according to a predetermined time law. The set speed thereby shifts towards the predetermine idling speed.