The functioning of the ALFB depends on various parameters:
- air and coolant temperatures when the ignition is turned on (see fig. 3.25);
- in high mountain regions, depending on the air temperature, ALFB switches off much later. Thus, the excitation time of the solenoid valve is increased;
- load and engine speed: for reasons of pollution and noise removal, AFLB is activated:
- if the coolant temperature is between 65°C and 80°C;
- if the engine speed is between 1350 and 1900 min-1;
- In all cases, ALFB is deactivated if the engine speed exceeds 3050 rpm-1 when the engine is running at full load.
Pic. 3.25. Graph of operation of the ALFB solenoid valve depending on air and coolant temperatures