Engine Warm-Up Phase

After starting, the engine still requires an enriched mixture for some time, since some fuel continues to condense in the intake system. For this purpose, 'after-start enrichment' is provided. For a certain time, depending on temperature, a larger amount of fuel is supplied. The control unit obtains the necessary engine temperature information from the coolant temperature sensor.

Relatively viscous engine oil causes increased internal friction when the engine is cold. Therefore, greater effort (richer mixture) is required to maintain the required engine speed. The supply of the enriched mixture is provided by the idle air control valve mentioned above.