|
曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
AUXILIARY POWER UNIT Description Vol. 2 05.10.9
Oct 05/06
APU Fuel Pump and Shutoff Valve Figure 05.10.5
APU Fuel Control Unit
The APU fuel control unit (FCU) is driven by the accessory gearbox, and meters fuel to the combustor under command of the electronic control unit (ECU). The APU fuel control unit is equipped with an internal solenoid-operated fuel shutoff valve that is commanded open and closed by the APU ECU, controlling fuel to the APU fuel control unit. In addition to controlling fuel shutoff, the ECU regulates fuel flow output from the fuel control unit, ensuring proper APU operating speed and temperature ranges.
AUXILIARY POWER UNIT Description Vol. 2 05.10.10
Oct 05/06
During normal or automatic APU shutdown, a simulated overspeed signal is generated within the ECU, commanding closure of the fuel control unit’s solenoid shutoff valve. Closing this valve causes an isolation of fuel supply to the APU’s fuel control unit, resulting in APU shutdown.
APU Negative-G Shutoff Valve
The APU negative-G shutoff valve opens and closes when the PWR FUEL switch/light is pressed. If the valve fails to close when the PWR FUEL switch/light is pressed out, the APU NEG G SOV caution message is displayed.
If a negative-G condition exists or the APU fuel pump fails, a one-way check valve, that operates based on positive differential pressure, allows fuel from the negative-G shutoff valve to feed the APU. An additional one-way check valve prevents this alternate fuel from entering the fuel-oil heat exchanger.
In the event of an actual APU fire, the negative-G shutoff valve is commanded closed when the APU FIRE PUSH switch/light is activated. If the valve fails to close, the left engine’s motive flow continues to supply fuel to the APU fuel control unit, and the APU NEG G SOV caution EICAS message is displayed. Under this condition, it is necessary to shutdown the left engine in order to shut off the fuel supply to the APU.
NOTE
If the APU fuel pump is not operable, the APU has an operating time limit from start-up until shutdown, due to insufficient cooling of the generator adapter oil. Refer to FUEL ATA 28 of the Minimum Equipment List for the allowable operating time limit.
AUXILIARY POWER UNIT Description Vol. 2 05.10.11
Oct 05/06
Negative.G Shutoff Valve and FCU
Figure 05.10.6
AUXILIARY POWER UNIT Description Vol. 2 05.10.12
Oct 05/06
Description
APU start and ignition is automatically controlled by the APU electronic control unit.
Components and Operation
APU Battery
The 24-volt, 43-ampere-hour battery is located below the APU enclosure, and provides cranking power to turn the APU starter. A minimum of 22 volts is required for starter motor operation. In the event of APU battery rundown, external DC power may be used to supply the starter via the APU battery direct bus.
中国公务机网 www.gongwuji.com
公务机翻译 www.aviation.cn
本文链接地址：庞巴迪挑战者605公务机机组操作手册 CL605-辅助动力装置 AUXILIARY_POWER_UNIT(5)
| 
