DOC AIRBUS | AMM A320FCOMPRESSOR CONTROL - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The Variable Stator Vane (VSV) and the Variable Bleed Valve (VBV) are controlled by the ECU.
The VSV system controls the air flow (primary) through the compressor downstream of the booster. The variable stator vane actuators position the inlet guide vanes and stator vanes as scheduled by the ECU through HMU.
The VBV system automatically schedules the total opening by positioning the valves as a function of corrected core and corrected fan speed.
** ON A/C NOT FOR ALL The Variable Stator Vane (VSV) and the Variable Bleed Valve (VBV) are controlled by the ECU.
The VSV system controls the air flow (primary) through the compressor downstream of the booster. The variable stator vane actuators position the inlet guide vanes and stator vanes as scheduled by the ECU through HMU.
The VBV system automatically schedules the total opening by positioning the valves as a function of corrected core and corrected fan speed.
2. Variable Stator Vane System (VSV)
(Ref. AMM D/O 75-32-00-00)
The VSV system maintains satisfactory the compressor performance over a wide range of operating conditions. The system varies the angle of the inlet guide vanes and the 3 stages of variable vanes, to aero-dynamically match the low pressure stages of compression with the high pressure stages. This variation of vane position changes the effective angle at which the air flows across the compresssor blades and vanes. The angle determines the compression characterictics (direction and velocity) for any particular stage of compression.
** ON A/C NOT FOR ALL (Ref. AMM D/O 75-32-00-00)
The VSV system maintains satisfactory the compressor performance over a wide range of operating conditions. The system varies the angle of the inlet guide vanes and the 3 stages of variable vanes, to aero-dynamically match the low pressure stages of compression with the high pressure stages. This variation of vane position changes the effective angle at which the air flows across the compresssor blades and vanes. The angle determines the compression characterictics (direction and velocity) for any particular stage of compression.
3. Variable Bleed Valve System (VBV)
(Ref. AMM D/O 75-31-00-00)
At low core engine speeds the booster provide more air than the core engine can utilize. To match the booster discharge airflow to the core engine requirements at low speed, excess air is bleed off through Variable Bleed Valves (VBV) into the fan discharge air stream. At higher engine speeds the VBV are closed so that all the booster discharge (primary air flow) enters the core engine. The VBV are scheduled as a function of corrected core engine speed and corrected fan speed and receive this signal from the HP compressor airflow control system. (The VBV system is controlled by the ECU through the HMU.)
(Ref. AMM D/O 75-31-00-00)
At low core engine speeds the booster provide more air than the core engine can utilize. To match the booster discharge airflow to the core engine requirements at low speed, excess air is bleed off through Variable Bleed Valves (VBV) into the fan discharge air stream. At higher engine speeds the VBV are closed so that all the booster discharge (primary air flow) enters the core engine. The VBV are scheduled as a function of corrected core engine speed and corrected fan speed and receive this signal from the HP compressor airflow control system. (The VBV system is controlled by the ECU through the HMU.)